Abstract

Broadband femtosecond (fs) two-photon laser-induced fluorescence (TP-LIF) of the B1Σ+X1Σ+, Hopfield–Birge system of carbon monoxide (CO) is believed to have two major advantages compared to narrowband nanosecond excitation. It should (i) minimize the effects of pressure-dependent absorption line broadening and shifting, and (ii) produce pressure-independent TP-LIF signals as the effect of increased quenching due to molecular collisions is offset by the increase in number density. However, there is an observed nonlinear drop in the CO TP-LIF signal with increasing pressure. In this work, we systematically investigate the relative impact of potential deexcitation mechanisms, including collisional quenching, forward lasing, attenuation of the source laser by the test cell windows or by the gas media, and a 2+1 photoionization process. As expected, line broadening and collisional quenching play minor roles in the pressure-scaling behavior, but the CO fs TP-LIF signals deviate from theory primarily because of two major reasons. First, attenuation of the excitation laser at high pressures significantly reduces the laser irradiance available at the probe volume. Second, a 2+1 photoionization process becomes significant as the number density increases with pressure and acts as a major deexcitation pathway. This work summarizes the phenomena and strategies that need to be considered for performing CO fs TP-LIF at high pressures.

© 2019 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Femtosecond, two-photon, laser-induced fluorescence (TP-LIF) measurement of CO in high-pressure flames

K. Arafat Rahman, Karna S. Patel, Mikhail N. Slipchenko, Terrence R. Meyer, Zhili Zhang, Yue Wu, James R. Gord, and Sukesh Roy
Appl. Opt. 57(20) 5666-5671 (2018)

Quantitative femtosecond, two-photon laser-induced fluorescence of atomic oxygen in high-pressure flames

K. Arafat Rahman, Venkat Athmanathan, Mikhail N. Slipchenko, Sukesh Roy, James R. Gord, Zhili Zhang, and Terrence R. Meyer
Appl. Opt. 58(8) 1984-1990 (2019)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (9)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (2)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription