Title :
Stimulated Raman shifting of the Nd:YAG fourth harmonic (266 nm) in H2, HD, and D2
Author :
Haner, David A. ; McDermid, I. Stuart
Author_Institution :
Dept. of Chem., California State Polytech. Univ., Pomona, CA, USA
fDate :
7/1/1990 12:00:00 AM
Abstract :
The dependence of the first Stokes stimulated Raman conversion efficiency of fourth-harmonic radiation from a Nd:YAG laser at 266 nm has been studied for the isotopic species H2, HD, and D2 as a function of gas pressure and laser energy using a low numerical aperture (~4.5×10-3) pumping geometry. While the laser energy threshold for first Stokes conversion is seen to vary significantly between the species it has been found that photon conversion efficiencies of at least 50% can be achieved for all of them for laser pump energies at 266 nm ⩽50 mJ/pulse. This study provides a new measurement of the differential cross section for stimulated Raman scattering in HD of 8.1±2.4×10-29 cm2/sr at 266 nm and at high pressures, and agreement is found with previous measurements of the cross sections for H2 and D2. The results have been used to optimize the laser transmitter system for a differential absorption lidar (DIAL) system to measure tropospheric ozone concentration profiles
Keywords :
atmospheric composition; atmospheric measuring apparatus; hydrogen neutral molecules; laser beams; optical harmonic generation; optical pumping; optical radar; ozone; remote sensing by laser beam; stimulated Raman scattering; troposphere; 266 nm; 50 percent; D2; H2; HD; Nd:YAG laser; O3; YAG:Nd; YAl5O12:Nd; differential absorption lidar; differential cross section; first Stokes stimulated Raman conversion efficiency; fourth harmonic; gas pressure; isotopic species; laser energy; laser energy threshold; laser pump energies; laser transmitter system; low numerical aperture; photon conversion efficiencies; pumping geometry; stimulated Raman scattering; stimulated Raman shifting; tropospheric ozone concentration profiles; Apertures; Gas lasers; Geometrical optics; High definition video; Laser excitation; Optical pulses; Pump lasers; Raman scattering; Stimulated emission; Transmitters;
Journal_Title :
Quantum Electronics, IEEE Journal of
