Abstract

Quantum cascade lasers are proving to be instrumental in the development of compact frequency comb sources at mid-infrared and terahertz frequencies. Here we demonstrate a heterogeneous terahertz quantum cascade laser with two active regions spaced exactly by one octave. Both active regions are based on a four-quantum well laser design and they emit a combined 3 mW peak power at 15 K in pulsed mode. The two central frequencies are 2.3 THz (bandwidth 300 GHz) and 4.6 THz (bandwidth 270 GHz). The structure is engineered in a way that allows simultaneous operation of the two active regions in the comb regime, serving as a double comb source as well as a test bench structure for all waveguide internal self-referencing techniques. Narrow RF beatnotes (∼ 15 kHz) are recorded showing the simultaneous operation of the two combs, whose free-running coherence properties are investigated by means of beatnote spectroscopy performed both with an external detector and via self-mixing. Comb operation in a highly dispersive region (4.6 THz) relying only on gain bandwidth engineering shows the potential for broad spectral coverage with compact comb sources.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Full Article  |  PDF Article
OSA Recommended Articles
Ultra-low noise all polarization-maintaining Er fiber-based optical frequency combs facilitated with a graphene modulator

N. Kuse, C.-C. Lee, J. Jiang, C. Mohr, T. R. Schibli, and M.E. Fermann
Opt. Express 23(19) 24342-24350 (2015)

Measurement of carrier envelope offset frequency for a 10 GHz etalon-stabilized semiconductor optical frequency comb

M. Akbulut, J. Davila-Rodriguez, I. Ozdur, F. Quinlan, S. Ozharar, N. Hoghooghi, and P.J. Delfyett
Opt. Express 19(18) 16851-16865 (2011)

Full stabilization and characterization of an optical frequency comb from a diode-pumped solid-state laser with GHz repetition rate

Sargis Hakobyan, Valentin J. Wittwer, Pierre Brochard, Kutan Gürel, Stéphane Schilt, Aline S. Mayer, Ursula Keller, and Thomas Südmeyer
Opt. Express 25(17) 20437-20453 (2017)

References

  • View by:
  • |
  • |
  • |

  1. T. Udem, R. Holzwarth, and T. W. Hänsch, “Optical frequency metrology,” Nature 416, 233–237 (2002).
    [Crossref] [PubMed]
  2. T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
    [Crossref] [PubMed]
  3. S. A. Diddams, “The evolving optical frequency comb [Invited],” JOSA B 27, B51–B62 (2010).
    [Crossref]
  4. I. Coddington, N. Newbury, and W. Swann, “Dual-comb spectroscopy,” Optica 3, 414–426 (2016).
    [Crossref]
  5. M. Tonouchi, “Cutting-edge terahertz technology,” Nat Photon 1, 97–105 (2007).
    [Crossref]
  6. G. Villares, A. Hugi, S. Blaser, and J. Faist, “Dual-comb spectroscopy based on quantum-cascade-laser frequency combs,” Nat Commun 55192 (2014).
    [Crossref] [PubMed]
  7. J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, “Quantum Cascade Laser Frequency Combs,” Nanophotonics 5, 272–291 (2016).
    [Crossref]
  8. A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
    [Crossref] [PubMed]
  9. D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
    [Crossref]
  10. M. Rösch, G. Scalari, M. Beck, and J. Faist, “Octave-spanning semiconductor laser,” Nat. Photonics 9, 42–47 (2015).
    [Crossref]
  11. Y. Yang, D. Burghoff, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz multiheterodyne spectroscopy using laser frequency combs,” Optica 3, 499–502 (2016).
    [Crossref]
  12. J. Westberg, L. Sterczewsk, and G. Wysocki, “Mid-infrared multiheterodyne spectroscopy with phase-locked quantum cascade lasers,” Appl. Phys. Lett. 110, 141108 (2017).
    [Crossref]
  13. G. Villares, J. Wolf, D. Kazakov, M. J. Süess, A. Hugi, M. Beck, and J. Faist, “On-chip dual-comb based on quantum cascade laser frequency combs,” Appl. Phys. Lett. 107251104 (2015).
    [Crossref]
  14. M. Rösch, G. Scalari, G. Villares, L. Bosco, M. Beck, and J. Faist, “On-chip, self-detected terahertz dual-comb source,” Appl. Phys. Lett. 108, 171104 (2016).
    [Crossref]
  15. F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
    [Crossref]
  16. H. Telle, G. Steinmeyer, A. Dunlop, J. Stenger, D. Sutter, and U. Keller, “Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and ultrashort pulse generation,” Appl. Phys. B 69, 327–332 (1999).
    [Crossref]
  17. D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis,” Science 288, 635–639 (2000).
    [Crossref] [PubMed]
  18. S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
    [Crossref] [PubMed]
  19. M. Rösch, M. Beck, S. Martin, D. Bachmann, K. Unterrainer, J. Faist, and G. Scalari, “Heterogeneous terahertz quantum cascade lasers exceeding 1.9 THz spectral bandwidth and featuring dual comb operation,” Nanophotonics 7, 237–242 (2018).
    [Crossref]
  20. C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
    [Crossref]
  21. Y. Yang, A. Paulsen, D. Burghoff, J. L. Reno, and Q. Hu, “Lateral Heterogeneous Integration of Quantum Cascade Lasers,” ACS Photonics 5, 2742 (2018).
    [Crossref]
  22. M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
    [Crossref]
  23. K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
    [Crossref]
  24. J. Lloyd-Hughes, G. Scalari, A. van Kolck, M. Fischer, M. Beck, and J. Faist, “Coupling terahertz radiation between sub-wavelength metal-metal waveguides and free space using monolithically integrated horn antennae,” Opt. Express 17, 18387–18393 (2009).
    [Crossref] [PubMed]
  25. D. Bachmann, M. Rösch, M. J. Süess, M. Beck, K. Unterrainer, J. Darmo, J. Faist, and G. Scalari, “Short pulse generation and mode control of broadband terahertz quantum cascade lasers,” Optica 3, 1087–1094 (2016).
    [Crossref]
  26. E. Palik, “Gallium arsenide (gaas),” in Handbook of optical constants of solids, E. D. Palik, ed. (Academic Press Inc., Orlando, Florida, 1985), pp. 429–443.
    [Crossref]
  27. M. Wienold, B. Röben, L. Schrottke, and H. T. Grahn, “Evidence for frequency comb emission from a Fabry-Pérot terahertz quantum-cascade laser,” Opt. Express 22, 30410–30424 (2014).
    [Crossref]
  28. L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
    [Crossref]

2018 (2)

M. Rösch, M. Beck, S. Martin, D. Bachmann, K. Unterrainer, J. Faist, and G. Scalari, “Heterogeneous terahertz quantum cascade lasers exceeding 1.9 THz spectral bandwidth and featuring dual comb operation,” Nanophotonics 7, 237–242 (2018).
[Crossref]

Y. Yang, A. Paulsen, D. Burghoff, J. L. Reno, and Q. Hu, “Lateral Heterogeneous Integration of Quantum Cascade Lasers,” ACS Photonics 5, 2742 (2018).
[Crossref]

2017 (1)

J. Westberg, L. Sterczewsk, and G. Wysocki, “Mid-infrared multiheterodyne spectroscopy with phase-locked quantum cascade lasers,” Appl. Phys. Lett. 110, 141108 (2017).
[Crossref]

2016 (7)

M. Rösch, G. Scalari, G. Villares, L. Bosco, M. Beck, and J. Faist, “On-chip, self-detected terahertz dual-comb source,” Appl. Phys. Lett. 108, 171104 (2016).
[Crossref]

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, “Quantum Cascade Laser Frequency Combs,” Nanophotonics 5, 272–291 (2016).
[Crossref]

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

I. Coddington, N. Newbury, and W. Swann, “Dual-comb spectroscopy,” Optica 3, 414–426 (2016).
[Crossref]

Y. Yang, D. Burghoff, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz multiheterodyne spectroscopy using laser frequency combs,” Optica 3, 499–502 (2016).
[Crossref]

D. Bachmann, M. Rösch, M. J. Süess, M. Beck, K. Unterrainer, J. Darmo, J. Faist, and G. Scalari, “Short pulse generation and mode control of broadband terahertz quantum cascade lasers,” Optica 3, 1087–1094 (2016).
[Crossref]

2015 (2)

M. Rösch, G. Scalari, M. Beck, and J. Faist, “Octave-spanning semiconductor laser,” Nat. Photonics 9, 42–47 (2015).
[Crossref]

G. Villares, J. Wolf, D. Kazakov, M. J. Süess, A. Hugi, M. Beck, and J. Faist, “On-chip dual-comb based on quantum cascade laser frequency combs,” Appl. Phys. Lett. 107251104 (2015).
[Crossref]

2014 (3)

G. Villares, A. Hugi, S. Blaser, and J. Faist, “Dual-comb spectroscopy based on quantum-cascade-laser frequency combs,” Nat Commun 55192 (2014).
[Crossref] [PubMed]

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

M. Wienold, B. Röben, L. Schrottke, and H. T. Grahn, “Evidence for frequency comb emission from a Fabry-Pérot terahertz quantum-cascade laser,” Opt. Express 22, 30410–30424 (2014).
[Crossref]

2012 (1)

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref] [PubMed]

2010 (1)

S. A. Diddams, “The evolving optical frequency comb [Invited],” JOSA B 27, B51–B62 (2010).
[Crossref]

2009 (2)

J. Lloyd-Hughes, G. Scalari, A. van Kolck, M. Fischer, M. Beck, and J. Faist, “Coupling terahertz radiation between sub-wavelength metal-metal waveguides and free space using monolithically integrated horn antennae,” Opt. Express 17, 18387–18393 (2009).
[Crossref] [PubMed]

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

2008 (1)

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

2007 (1)

M. Tonouchi, “Cutting-edge terahertz technology,” Nat Photon 1, 97–105 (2007).
[Crossref]

2003 (1)

C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
[Crossref]

2002 (2)

T. Udem, R. Holzwarth, and T. W. Hänsch, “Optical frequency metrology,” Nature 416, 233–237 (2002).
[Crossref] [PubMed]

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

2000 (2)

D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis,” Science 288, 635–639 (2000).
[Crossref] [PubMed]

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

1999 (1)

H. Telle, G. Steinmeyer, A. Dunlop, J. Stenger, D. Sutter, and U. Keller, “Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and ultrashort pulse generation,” Appl. Phys. B 69, 327–332 (1999).
[Crossref]

Ajili, L.

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

Amanti, M. I.

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

Araujo-Hauck, C.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

Bachmann, D.

M. Rösch, M. Beck, S. Martin, D. Bachmann, K. Unterrainer, J. Faist, and G. Scalari, “Heterogeneous terahertz quantum cascade lasers exceeding 1.9 THz spectral bandwidth and featuring dual comb operation,” Nanophotonics 7, 237–242 (2018).
[Crossref]

D. Bachmann, M. Rösch, M. J. Süess, M. Beck, K. Unterrainer, J. Darmo, J. Faist, and G. Scalari, “Short pulse generation and mode control of broadband terahertz quantum cascade lasers,” Optica 3, 1087–1094 (2016).
[Crossref]

Bartalini, S.

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Beck, M.

M. Rösch, M. Beck, S. Martin, D. Bachmann, K. Unterrainer, J. Faist, and G. Scalari, “Heterogeneous terahertz quantum cascade lasers exceeding 1.9 THz spectral bandwidth and featuring dual comb operation,” Nanophotonics 7, 237–242 (2018).
[Crossref]

M. Rösch, G. Scalari, G. Villares, L. Bosco, M. Beck, and J. Faist, “On-chip, self-detected terahertz dual-comb source,” Appl. Phys. Lett. 108, 171104 (2016).
[Crossref]

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, “Quantum Cascade Laser Frequency Combs,” Nanophotonics 5, 272–291 (2016).
[Crossref]

D. Bachmann, M. Rösch, M. J. Süess, M. Beck, K. Unterrainer, J. Darmo, J. Faist, and G. Scalari, “Short pulse generation and mode control of broadband terahertz quantum cascade lasers,” Optica 3, 1087–1094 (2016).
[Crossref]

M. Rösch, G. Scalari, M. Beck, and J. Faist, “Octave-spanning semiconductor laser,” Nat. Photonics 9, 42–47 (2015).
[Crossref]

G. Villares, J. Wolf, D. Kazakov, M. J. Süess, A. Hugi, M. Beck, and J. Faist, “On-chip dual-comb based on quantum cascade laser frequency combs,” Appl. Phys. Lett. 107251104 (2015).
[Crossref]

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

J. Lloyd-Hughes, G. Scalari, A. van Kolck, M. Fischer, M. Beck, and J. Faist, “Coupling terahertz radiation between sub-wavelength metal-metal waveguides and free space using monolithically integrated horn antennae,” Opt. Express 17, 18387–18393 (2009).
[Crossref] [PubMed]

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

Beere, H.

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

Belyanin, A.

C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
[Crossref]

Benea-Chelmus, I.-C.

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

Blaser, S.

G. Villares, A. Hugi, S. Blaser, and J. Faist, “Dual-comb spectroscopy based on quantum-cascade-laser frequency combs,” Nat Commun 55192 (2014).
[Crossref] [PubMed]

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref] [PubMed]

Bonzon, C.

J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, “Quantum Cascade Laser Frequency Combs,” Nanophotonics 5, 272–291 (2016).
[Crossref]

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

Borri, S.

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Bosco, L.

M. Rösch, G. Scalari, G. Villares, L. Bosco, M. Beck, and J. Faist, “On-chip, self-detected terahertz dual-comb source,” Appl. Phys. Lett. 108, 171104 (2016).
[Crossref]

Burghoff, D.

Y. Yang, A. Paulsen, D. Burghoff, J. L. Reno, and Q. Hu, “Lateral Heterogeneous Integration of Quantum Cascade Lasers,” ACS Photonics 5, 2742 (2018).
[Crossref]

Y. Yang, D. Burghoff, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz multiheterodyne spectroscopy using laser frequency combs,” Optica 3, 499–502 (2016).
[Crossref]

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

Cai, X.

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

Campo, G.

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Cancio, P.

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Capasso, F.

C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
[Crossref]

Cappelli, F.

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Cho, A.

C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
[Crossref]

Coddington, I.

Cundiff, S. T.

D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis,” Science 288, 635–639 (2000).
[Crossref] [PubMed]

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

D’Odorico, S.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

Darmo, J.

Davies, G.

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

De Natale, P.

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Diddams, S. A.

S. A. Diddams, “The evolving optical frequency comb [Invited],” JOSA B 27, B51–B62 (2010).
[Crossref]

D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis,” Science 288, 635–639 (2000).
[Crossref] [PubMed]

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

Dunlop, A.

H. Telle, G. Steinmeyer, A. Dunlop, J. Stenger, D. Sutter, and U. Keller, “Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and ultrashort pulse generation,” Appl. Phys. B 69, 327–332 (1999).
[Crossref]

Faist, J.

M. Rösch, M. Beck, S. Martin, D. Bachmann, K. Unterrainer, J. Faist, and G. Scalari, “Heterogeneous terahertz quantum cascade lasers exceeding 1.9 THz spectral bandwidth and featuring dual comb operation,” Nanophotonics 7, 237–242 (2018).
[Crossref]

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

M. Rösch, G. Scalari, G. Villares, L. Bosco, M. Beck, and J. Faist, “On-chip, self-detected terahertz dual-comb source,” Appl. Phys. Lett. 108, 171104 (2016).
[Crossref]

J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, “Quantum Cascade Laser Frequency Combs,” Nanophotonics 5, 272–291 (2016).
[Crossref]

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

D. Bachmann, M. Rösch, M. J. Süess, M. Beck, K. Unterrainer, J. Darmo, J. Faist, and G. Scalari, “Short pulse generation and mode control of broadband terahertz quantum cascade lasers,” Optica 3, 1087–1094 (2016).
[Crossref]

M. Rösch, G. Scalari, M. Beck, and J. Faist, “Octave-spanning semiconductor laser,” Nat. Photonics 9, 42–47 (2015).
[Crossref]

G. Villares, J. Wolf, D. Kazakov, M. J. Süess, A. Hugi, M. Beck, and J. Faist, “On-chip dual-comb based on quantum cascade laser frequency combs,” Appl. Phys. Lett. 107251104 (2015).
[Crossref]

G. Villares, A. Hugi, S. Blaser, and J. Faist, “Dual-comb spectroscopy based on quantum-cascade-laser frequency combs,” Nat Commun 55192 (2014).
[Crossref] [PubMed]

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref] [PubMed]

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

J. Lloyd-Hughes, G. Scalari, A. van Kolck, M. Fischer, M. Beck, and J. Faist, “Coupling terahertz radiation between sub-wavelength metal-metal waveguides and free space using monolithically integrated horn antennae,” Opt. Express 17, 18387–18393 (2009).
[Crossref] [PubMed]

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

Fischer, M.

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

J. Lloyd-Hughes, G. Scalari, A. van Kolck, M. Fischer, M. Beck, and J. Faist, “Coupling terahertz radiation between sub-wavelength metal-metal waveguides and free space using monolithically integrated horn antennae,” Opt. Express 17, 18387–18393 (2009).
[Crossref] [PubMed]

Galli, I.

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Gallo, P.

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

Gao, J.-R.

Y. Yang, D. Burghoff, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz multiheterodyne spectroscopy using laser frequency combs,” Optica 3, 499–502 (2016).
[Crossref]

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

Giusfredi, G.

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Gmachl, C.

C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
[Crossref]

Graf, U. U.

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

Grahn, H. T.

Hall, J. L.

D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis,” Science 288, 635–639 (2000).
[Crossref] [PubMed]

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

Han, N.

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

Hänsch, T. W.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

T. Udem, R. Holzwarth, and T. W. Hänsch, “Optical frequency metrology,” Nature 416, 233–237 (2002).
[Crossref] [PubMed]

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

Hayton, D. J.

Y. Yang, D. Burghoff, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz multiheterodyne spectroscopy using laser frequency combs,” Optica 3, 499–502 (2016).
[Crossref]

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

Hinkov, B.

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Hofstetter, D.

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

Holzwarth, R.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

T. Udem, R. Holzwarth, and T. W. Hänsch, “Optical frequency metrology,” Nature 416, 233–237 (2002).
[Crossref] [PubMed]

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

Hu, Q.

Y. Yang, A. Paulsen, D. Burghoff, J. L. Reno, and Q. Hu, “Lateral Heterogeneous Integration of Quantum Cascade Lasers,” ACS Photonics 5, 2742 (2018).
[Crossref]

Y. Yang, D. Burghoff, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz multiheterodyne spectroscopy using laser frequency combs,” Optica 3, 499–502 (2016).
[Crossref]

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

Hugi, A.

J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, “Quantum Cascade Laser Frequency Combs,” Nanophotonics 5, 272–291 (2016).
[Crossref]

G. Villares, J. Wolf, D. Kazakov, M. J. Süess, A. Hugi, M. Beck, and J. Faist, “On-chip dual-comb based on quantum cascade laser frequency combs,” Appl. Phys. Lett. 107251104 (2015).
[Crossref]

G. Villares, A. Hugi, S. Blaser, and J. Faist, “Dual-comb spectroscopy based on quantum-cascade-laser frequency combs,” Nat Commun 55192 (2014).
[Crossref] [PubMed]

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref] [PubMed]

Jones, D. J.

D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis,” Science 288, 635–639 (2000).
[Crossref] [PubMed]

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

Justen, M.

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

Kao, T.-Y.

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

Kapon, E.

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

Kazakov, D.

G. Villares, J. Wolf, D. Kazakov, M. J. Süess, A. Hugi, M. Beck, and J. Faist, “On-chip dual-comb based on quantum cascade laser frequency combs,” Appl. Phys. Lett. 107251104 (2015).
[Crossref]

Keller, U.

H. Telle, G. Steinmeyer, A. Dunlop, J. Stenger, D. Sutter, and U. Keller, “Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and ultrashort pulse generation,” Appl. Phys. B 69, 327–332 (1999).
[Crossref]

Kentischer, T.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

Linfield, E.

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

Liu, H. C.

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref] [PubMed]

Lloyd-Hughes, J.

Manescau, A.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

Martin, S.

M. Rösch, M. Beck, S. Martin, D. Bachmann, K. Unterrainer, J. Faist, and G. Scalari, “Heterogeneous terahertz quantum cascade lasers exceeding 1.9 THz spectral bandwidth and featuring dual comb operation,” Nanophotonics 7, 237–242 (2018).
[Crossref]

Mazzotti, D.

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Mertens, M.

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

Murphy, M. T.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

Newbury, N.

Ohtani, K.

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

Owschimikow, N.

C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
[Crossref]

Palik, E.

E. Palik, “Gallium arsenide (gaas),” in Handbook of optical constants of solids, E. D. Palik, ed. (Academic Press Inc., Orlando, Florida, 1985), pp. 429–443.
[Crossref]

Pasquini, L.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

Paulsen, A.

Y. Yang, A. Paulsen, D. Burghoff, J. L. Reno, and Q. Hu, “Lateral Heterogeneous Integration of Quantum Cascade Lasers,” ACS Photonics 5, 2742 (2018).
[Crossref]

Peabody, M.

C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
[Crossref]

Ranka, J. K.

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis,” Science 288, 635–639 (2000).
[Crossref] [PubMed]

Reno, J. L.

Y. Yang, A. Paulsen, D. Burghoff, J. L. Reno, and Q. Hu, “Lateral Heterogeneous Integration of Quantum Cascade Lasers,” ACS Photonics 5, 2742 (2018).
[Crossref]

Y. Yang, D. Burghoff, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz multiheterodyne spectroscopy using laser frequency combs,” Optica 3, 499–502 (2016).
[Crossref]

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

Ritchie, D.

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

Röben, B.

Rösch, M.

M. Rösch, M. Beck, S. Martin, D. Bachmann, K. Unterrainer, J. Faist, and G. Scalari, “Heterogeneous terahertz quantum cascade lasers exceeding 1.9 THz spectral bandwidth and featuring dual comb operation,” Nanophotonics 7, 237–242 (2018).
[Crossref]

M. Rösch, G. Scalari, G. Villares, L. Bosco, M. Beck, and J. Faist, “On-chip, self-detected terahertz dual-comb source,” Appl. Phys. Lett. 108, 171104 (2016).
[Crossref]

J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, “Quantum Cascade Laser Frequency Combs,” Nanophotonics 5, 272–291 (2016).
[Crossref]

D. Bachmann, M. Rösch, M. J. Süess, M. Beck, K. Unterrainer, J. Darmo, J. Faist, and G. Scalari, “Short pulse generation and mode control of broadband terahertz quantum cascade lasers,” Optica 3, 1087–1094 (2016).
[Crossref]

M. Rösch, G. Scalari, M. Beck, and J. Faist, “Octave-spanning semiconductor laser,” Nat. Photonics 9, 42–47 (2015).
[Crossref]

Rudra, A.

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

Scalari, G.

M. Rösch, M. Beck, S. Martin, D. Bachmann, K. Unterrainer, J. Faist, and G. Scalari, “Heterogeneous terahertz quantum cascade lasers exceeding 1.9 THz spectral bandwidth and featuring dual comb operation,” Nanophotonics 7, 237–242 (2018).
[Crossref]

M. Rösch, G. Scalari, G. Villares, L. Bosco, M. Beck, and J. Faist, “On-chip, self-detected terahertz dual-comb source,” Appl. Phys. Lett. 108, 171104 (2016).
[Crossref]

J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, “Quantum Cascade Laser Frequency Combs,” Nanophotonics 5, 272–291 (2016).
[Crossref]

D. Bachmann, M. Rösch, M. J. Süess, M. Beck, K. Unterrainer, J. Darmo, J. Faist, and G. Scalari, “Short pulse generation and mode control of broadband terahertz quantum cascade lasers,” Optica 3, 1087–1094 (2016).
[Crossref]

M. Rösch, G. Scalari, M. Beck, and J. Faist, “Octave-spanning semiconductor laser,” Nat. Photonics 9, 42–47 (2015).
[Crossref]

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

J. Lloyd-Hughes, G. Scalari, A. van Kolck, M. Fischer, M. Beck, and J. Faist, “Coupling terahertz radiation between sub-wavelength metal-metal waveguides and free space using monolithically integrated horn antennae,” Opt. Express 17, 18387–18393 (2009).
[Crossref] [PubMed]

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

Schmidt, W.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

Schrottke, L.

Sergent, A.

C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
[Crossref]

Sivco, D.

C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
[Crossref]

Steinmetz, T.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

Steinmeyer, G.

H. Telle, G. Steinmeyer, A. Dunlop, J. Stenger, D. Sutter, and U. Keller, “Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and ultrashort pulse generation,” Appl. Phys. B 69, 327–332 (1999).
[Crossref]

Stenger, J.

H. Telle, G. Steinmeyer, A. Dunlop, J. Stenger, D. Sutter, and U. Keller, “Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and ultrashort pulse generation,” Appl. Phys. B 69, 327–332 (1999).
[Crossref]

Stentz, A.

D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis,” Science 288, 635–639 (2000).
[Crossref] [PubMed]

Sterczewsk, L.

J. Westberg, L. Sterczewsk, and G. Wysocki, “Mid-infrared multiheterodyne spectroscopy with phase-locked quantum cascade lasers,” Appl. Phys. Lett. 110, 141108 (2017).
[Crossref]

Stutzki, J.

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

Süess, M. J.

D. Bachmann, M. Rösch, M. J. Süess, M. Beck, K. Unterrainer, J. Darmo, J. Faist, and G. Scalari, “Short pulse generation and mode control of broadband terahertz quantum cascade lasers,” Optica 3, 1087–1094 (2016).
[Crossref]

G. Villares, J. Wolf, D. Kazakov, M. J. Süess, A. Hugi, M. Beck, and J. Faist, “On-chip dual-comb based on quantum cascade laser frequency combs,” Appl. Phys. Lett. 107251104 (2015).
[Crossref]

Sutter, D.

H. Telle, G. Steinmeyer, A. Dunlop, J. Stenger, D. Sutter, and U. Keller, “Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and ultrashort pulse generation,” Appl. Phys. B 69, 327–332 (1999).
[Crossref]

Swann, W.

Telle, H.

H. Telle, G. Steinmeyer, A. Dunlop, J. Stenger, D. Sutter, and U. Keller, “Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and ultrashort pulse generation,” Appl. Phys. B 69, 327–332 (1999).
[Crossref]

Terazzi, R.

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

Tonouchi, M.

M. Tonouchi, “Cutting-edge terahertz technology,” Nat Photon 1, 97–105 (2007).
[Crossref]

Turcinkova, D.

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

Udem, T.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

T. Udem, R. Holzwarth, and T. W. Hänsch, “Optical frequency metrology,” Nature 416, 233–237 (2002).
[Crossref] [PubMed]

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

Unterrainer, K.

M. Rösch, M. Beck, S. Martin, D. Bachmann, K. Unterrainer, J. Faist, and G. Scalari, “Heterogeneous terahertz quantum cascade lasers exceeding 1.9 THz spectral bandwidth and featuring dual comb operation,” Nanophotonics 7, 237–242 (2018).
[Crossref]

D. Bachmann, M. Rösch, M. J. Süess, M. Beck, K. Unterrainer, J. Darmo, J. Faist, and G. Scalari, “Short pulse generation and mode control of broadband terahertz quantum cascade lasers,” Optica 3, 1087–1094 (2016).
[Crossref]

van Kolck, A.

Villares, G.

M. Rösch, G. Scalari, G. Villares, L. Bosco, M. Beck, and J. Faist, “On-chip, self-detected terahertz dual-comb source,” Appl. Phys. Lett. 108, 171104 (2016).
[Crossref]

J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, “Quantum Cascade Laser Frequency Combs,” Nanophotonics 5, 272–291 (2016).
[Crossref]

G. Villares, J. Wolf, D. Kazakov, M. J. Süess, A. Hugi, M. Beck, and J. Faist, “On-chip dual-comb based on quantum cascade laser frequency combs,” Appl. Phys. Lett. 107251104 (2015).
[Crossref]

G. Villares, A. Hugi, S. Blaser, and J. Faist, “Dual-comb spectroscopy based on quantum-cascade-laser frequency combs,” Nat Commun 55192 (2014).
[Crossref] [PubMed]

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref] [PubMed]

Wang, I. C. C.

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

Westberg, J.

J. Westberg, L. Sterczewsk, and G. Wysocki, “Mid-infrared multiheterodyne spectroscopy with phase-locked quantum cascade lasers,” Appl. Phys. Lett. 110, 141108 (2017).
[Crossref]

Wienold, M.

Wilken, T.

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

Windeler, R. S.

D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis,” Science 288, 635–639 (2000).
[Crossref] [PubMed]

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

Wolf, J.

G. Villares, J. Wolf, D. Kazakov, M. J. Süess, A. Hugi, M. Beck, and J. Faist, “On-chip dual-comb based on quantum cascade laser frequency combs,” Appl. Phys. Lett. 107251104 (2015).
[Crossref]

Wysocki, G.

J. Westberg, L. Sterczewsk, and G. Wysocki, “Mid-infrared multiheterodyne spectroscopy with phase-locked quantum cascade lasers,” Appl. Phys. Lett. 110, 141108 (2017).
[Crossref]

Yang, Y.

Y. Yang, A. Paulsen, D. Burghoff, J. L. Reno, and Q. Hu, “Lateral Heterogeneous Integration of Quantum Cascade Lasers,” ACS Photonics 5, 2742 (2018).
[Crossref]

Y. Yang, D. Burghoff, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz multiheterodyne spectroscopy using laser frequency combs,” Optica 3, 499–502 (2016).
[Crossref]

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

Ye, J.

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

ACS Photonics (1)

Y. Yang, A. Paulsen, D. Burghoff, J. L. Reno, and Q. Hu, “Lateral Heterogeneous Integration of Quantum Cascade Lasers,” ACS Photonics 5, 2742 (2018).
[Crossref]

Appl. Phys. B (1)

H. Telle, G. Steinmeyer, A. Dunlop, J. Stenger, D. Sutter, and U. Keller, “Carrier-envelope offset phase control: A novel concept for absolute optical frequency measurement and ultrashort pulse generation,” Appl. Phys. B 69, 327–332 (1999).
[Crossref]

Appl. Phys. Lett. (3)

J. Westberg, L. Sterczewsk, and G. Wysocki, “Mid-infrared multiheterodyne spectroscopy with phase-locked quantum cascade lasers,” Appl. Phys. Lett. 110, 141108 (2017).
[Crossref]

G. Villares, J. Wolf, D. Kazakov, M. J. Süess, A. Hugi, M. Beck, and J. Faist, “On-chip dual-comb based on quantum cascade laser frequency combs,” Appl. Phys. Lett. 107251104 (2015).
[Crossref]

M. Rösch, G. Scalari, G. Villares, L. Bosco, M. Beck, and J. Faist, “On-chip, self-detected terahertz dual-comb source,” Appl. Phys. Lett. 108, 171104 (2016).
[Crossref]

IEE Elect. Lett. (1)

L. Ajili, G. Scalari, D. Hofstetter, M. Beck, J. Faist, H. Beere, G. Davies, E. Linfield, and D. Ritchie, “Continuous-wave operation of far-infrared quantum cascade lasers,” IEE Elect. Lett. 38, 1675–1676 (2002).
[Crossref]

IEEE J. Quantum Electron. (1)

C. Gmachl, A. Belyanin, D. Sivco, M. Peabody, N. Owschimikow, A. Sergent, F. Capasso, and A. Cho, “Optimzed second-harmonic generation in quantum cascade lasers,” IEEE J. Quantum Electron. 39, 1345–1355 (2003).
[Crossref]

JOSA B (1)

S. A. Diddams, “The evolving optical frequency comb [Invited],” JOSA B 27, B51–B62 (2010).
[Crossref]

Laser & Photonics Rev. (1)

F. Cappelli, G. Campo, I. Galli, G. Giusfredi, S. Bartalini, D. Mazzotti, P. Cancio, S. Borri, B. Hinkov, J. Faist, and P. De Natale, “Frequency stability characterization of a quantum cascade laser frequency comb,” Laser & Photonics Rev. 10, 623–630 (2016).
[Crossref]

Nanophotonics (2)

J. Faist, G. Villares, G. Scalari, M. Rösch, C. Bonzon, A. Hugi, and M. Beck, “Quantum Cascade Laser Frequency Combs,” Nanophotonics 5, 272–291 (2016).
[Crossref]

M. Rösch, M. Beck, S. Martin, D. Bachmann, K. Unterrainer, J. Faist, and G. Scalari, “Heterogeneous terahertz quantum cascade lasers exceeding 1.9 THz spectral bandwidth and featuring dual comb operation,” Nanophotonics 7, 237–242 (2018).
[Crossref]

Nat Commun (1)

G. Villares, A. Hugi, S. Blaser, and J. Faist, “Dual-comb spectroscopy based on quantum-cascade-laser frequency combs,” Nat Commun 55192 (2014).
[Crossref] [PubMed]

Nat Photon (1)

M. Tonouchi, “Cutting-edge terahertz technology,” Nat Photon 1, 97–105 (2007).
[Crossref]

Nat. Photonics (2)

D. Burghoff, T.-Y. Kao, N. Han, I. C. C. Wang, X. Cai, Y. Yang, D. J. Hayton, J.-R. Gao, J. L. Reno, and Q. Hu, “Terahertz laser frequency combs,” Nat. Photonics 8, 462–467 (2014).
[Crossref]

M. Rösch, G. Scalari, M. Beck, and J. Faist, “Octave-spanning semiconductor laser,” Nat. Photonics 9, 42–47 (2015).
[Crossref]

Nature (2)

A. Hugi, G. Villares, S. Blaser, H. C. Liu, and J. Faist, “Mid-infrared frequency comb based on a quantum cascade laser,” Nature 492, 229–233 (2012).
[Crossref] [PubMed]

T. Udem, R. Holzwarth, and T. W. Hänsch, “Optical frequency metrology,” Nature 416, 233–237 (2002).
[Crossref] [PubMed]

New J. Phys. (2)

M. I. Amanti, G. Scalari, R. Terazzi, M. Fischer, M. Beck, J. Faist, A. Rudra, P. Gallo, and E. Kapon, “Bound-to-continuum terahertz quantum cascade laser with a single-quantum-well phonon extraction/injection stage,” New J. Phys. 11, 125022 (2009).
[Crossref]

K. Ohtani, D. Turcinkova, C. Bonzon, I.-C. Benea-Chelmus, M. Beck, J. Faist, M. Justen, U. U. Graf, M. Mertens, and J. Stutzki, “High performance 4.7 thz gaas quantum cascade lasers based on four quantum wells,” New J. Phys. 18, 123004 (2016).
[Crossref]

Opt. Express (2)

Optica (3)

Phys. Rev. Lett. (1)

S. A. Diddams, D. J. Jones, J. Ye, S. T. Cundiff, J. L. Hall, J. K. Ranka, R. S. Windeler, R. Holzwarth, T. Udem, and T. W. Hänsch, “Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb,” Phys. Rev. Lett. 84, 5102–5105 (2000).
[Crossref] [PubMed]

Science (2)

D. J. Jones, S. A. Diddams, J. K. Ranka, A. Stentz, R. S. Windeler, J. L. Hall, and S. T. Cundiff, “Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis,” Science 288, 635–639 (2000).
[Crossref] [PubMed]

T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T. W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M. T. Murphy, T. Kentischer, W. Schmidt, and T. Udem, “Laser Frequency Combs for Astronomical Observations,” Science 321, 1335–1337 (2008).
[Crossref] [PubMed]

Other (1)

E. Palik, “Gallium arsenide (gaas),” in Handbook of optical constants of solids, E. D. Palik, ed. (Academic Press Inc., Orlando, Florida, 1985), pp. 429–443.
[Crossref]

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (8)

Fig. 1
Fig. 1 (a) Spectrum showing the simultaneous lasing at octave-spaced frequencies in pulsed operation (5% duty cycle at 1 kHz repetition frequency at 15 K) and in the inset the schematic of the heterogeneous QCL. (b) L-I-V curve for a 2.4 mm long, 80 µm wide laser ridge in pulsed mode (at 120 kHz and 5% duty cycle, square wave modulated at 30 Hz at 15 K). Peak power of 3mW is recorded. The orange resp. green marker show the spectral integrated intensities from (c) around the 2.3 THz resp. 4.6 THz FC, rescaled to the peak power, giving an estimate for the individual FC peak power in the mW range. (c) Series of recorded spectra as a function of the injected current of the same device operated as in (a). The evolution shows first lasing of the 4.6 THz active regions before both active regions lase simultaneously.
Fig. 2
Fig. 2 BN map from a 2.4 mm long and 80 µm wide QCL operated in pulsed (1 kHz repetition rate, 5 % duty cycle) at 13.3 K. We observe two regions where two single BNs at 15.1 GHz resp. 16.8 GHz are simultaneously present with a SNR of ∼35 dB resp. ∼20 dB. The assigning of the BNs was done by the simple argument of the expected frep from the frequency-dependent free spectral range of the QCL and is further addressed in the text.
Fig. 3
Fig. 3 (a) Spectrum of the two simultaneous existing FCs at 710 mA injection current of the BN map in Fig. 2. (b) Corresponding narrow BNs recorded through the bias-tee. (c) Calculated group refractive index ng for GaAs (green) and the simulated group refractive index for the QCL waveguide (red, using Comsol 5.0) together with values deduced from BNs measurement of the two combs, using ng = c/(2frepL) for multiple devices operating in two color comb regime. Inset: Multiple devices show lasing in a very dispersive region. The recorded FC BW shows the capability of the QCL of establishing a FC despite the approximate 0.08 change in the group refractive index.
Fig. 4
Fig. 4 Schematics of intermode BN spectroscopy setup. The SA on the bias line (SA2; highlighted in red) in the sketch can be used to verify the presence of to BNs as well as for detection of the self-mixing signal from the intermode BN spectroscopy. The laser is directly operated on a flow crysotat inside a home-made, step-scan and under vacuum FTIR (light blue area).
Fig. 5
Fig. 5 A 2.4 mm and 80 µm wide QCL was operated at 1 kHz repetition frequency with 100 µs long pulses at 16K. (a) Interferograms recorded from the DC signal (green) and RF signal (blue) of the Schottky detector. (b) Corresponding spectra showing the spectral coherence and confirming the comb nature around 2.3 THz.
Fig. 6
Fig. 6 (a) Self-mixing interferogram recorded from the 15.14 GHz BN in a step-scan FTIR. (b) Corresponding spectrum (azure blue) is compared to vertical displaced spectra in the two FC regions. Around 2.3 THz this self-mixing spectrum is clearly not generated by the modes of the 2.3 THz FC as measured by the DC (green) and RF (blue) spectrum from the Schottky measurement. Due the lacking detection bandwidth of the Schottky, the 4.6 THz components of the self-mixing spectrum is compared to a reference measurement by a commercial FTIR (Bruker 80v, DTGS detector). Despite the low resolution of the self-mixing spectra, the origin of the 15.14 GHz BN from modes centered at 4.6 THz is clearly verified.
Fig. 7
Fig. 7 (a) Down-mixed 15.15 GHz BN from a 2.4 mm device at 697 mA injection current operated at 500 Hz repetition frequency and 100 µs long pulses at 7 K. The BN shows red and blue shift during the same pulse. (b) Down-mixed signal from the simultaneous existing 16.79 GHz BN showing a blue shift. (c) Down-mixed signal from the BN beating at 1.64 GHz and the numerical BN beating (white) from (b) and (b), offset by −2 MHz for visibility. (d) Down-mixed 15.12 GHz BN from the same 2.4 mm device at 668 mA injection current operated at 1 kHz repetition frequency and 80 µs long pulses at 7.7 K. The BN shows a red shift. Inset: Slight change of the 15.12 GHz BN trace when the 16.79 GHz BN switches off. (e) Down-mixed signal from the simultaneous existing 16.79 GHz BN showing a blue shift. The BN switches off after ∼67 µs (dotted white line). The slight change at this time in the time trace of the 15.12 GHz signal could indicate coupling between the BNs. (f) Down-mixed signal from the BN beating at 1.64 GHz. The switching-off of the 16.79 GHz BN is reflected in the BN beating.
Fig. 8
Fig. 8 (a) Recorded QCL bias voltage over one 200 µs long pulse. (b) Down-mixed 16.79 GHz BN of the same 200 µs long pulse. Some trend from the voltage shows similarities to instantaneous frequency. (c) Numerically unchirped 16.78 GHz BN from the 2.3 THz FC which shows a narrow linewidth of 5.71 kHz.

Equations (2)

Equations on this page are rendered with MathJax. Learn more.

f n = f c e o + n f r e p ,
fast scope signal : ( ~ 180 M H z ) X ( t ) Hilbert Transform X ( t ) + 1 i Y ( t ) : analytical signal X ( t ) + 1 i Y ( t ) = A ( t ) exp [ i ϕ ( t ) ] : complex notation v ( t ) = 1 2 π d ϕ ( t ) d t : instantaneous frequency X ˜ ( t ) = A ( t ) exp [ i ϕ ( t ) ] exp [ i 2 π ( v c o n s t v ( t ) ) t ] : phase corrected scope signal

Metrics