Saturated polarization spectroscopy with a picosecond laser for quantitative concentration measurements
The collisional dependence of saturated polarization spectroscopy with a picosecond laser is investigated by probing hydroxyl in a flow cell. While nanosecond lasers have been used often for nonlinear diagnostic measurements of flame composition, picosecond lasers provide a potentially superior source for such techniques. Compared to a nanosecond laser, picosecond lasers produce significantly greater peak power for the same pulse energy, and this could improve the signal strength of multi-photon techniques such as degenerate four-wave mixing (DFWM) and polarization spectroscopy (PS). It has been suggested that the signal produced by such lasers would be less dependent on the collisional environment because the behavior of the molecular system probed by short-pulse lasers is governed more by the spectral width of the laser and the Doppler effect. To investigate the collisional dependence of the polarization spectroscopy signal generated with a picosecond laser, the authors probe the A{sup 2}{Sigma}{sup +}-X{sup 2}{Pi} (0,0) band of OH in a flow cell. In this well-controlled environment, the authors monitor the change in signal strength as they vary the buffer gas pressure by a factor of 50. Hydroxyl (OH) is created by photolysis of hydrogen peroxide using a Nd:YAG laser.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 755821
- Report Number(s):
- SAND2000-8402C; TRN: AH200021%%70
- Resource Relation:
- Conference: 2000 Laser Applications to Chemical and Environmental Analysis Topical Meeting, Santa Fe, NM (US), 02/11/2000; Other Information: PBD: 11 Feb 2000
- Country of Publication:
- United States
- Language:
- English
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