Title :
Generation of high-order rotational lines in hydrogen by four-wave Raman mixing in the femtosecond regime
Author :
Kawano, Hiroyuki ; Hirakawa, Yasuyuki ; Imasaka, Totaro
Author_Institution :
Dept. of Chem. Sci. & Technol., Kyushu Univ., Fukuoka, Japan
fDate :
2/1/1998 12:00:00 AM
Abstract :
More than 40 rotational Raman lines are generated using an 800-fs Ti:sapphire laser. The spectral region extends from the near-infrared to the far-ultraviolet with a considerably flat intensity distribution. The effects of laser polarization, pulsewidth, hydrogen pressure, and focusing conditions on the efficiencies of stimulated Raman scattering, four-wave Raman mixing, self-phase modulation, self-focusing, and harmonic generation are investigated. A white light continuum, generated by self-phase modulation, acts as a seed beam for the generation of high-order rotational lines through four-wave Raman mixing. Strong self-phase modulation, however, suppresses the generation of the Raman emission, due to a line broadening of the pump beam. Thus, optimization of experimental conditions is necessary for the efficient generation of high-order rotational lines
Keywords :
high-speed optical techniques; hydrogen; multiwave mixing; optical modulation; optical pumping; optical self-focusing; phase modulation; rotational states; sapphire; solid lasers; stimulated Raman scattering; titanium; 800 fs; far-ultraviolet; femtosecond regime; flat intensity distribution; focusing conditions; four-wave Raman mixing; fs Ti:sapphire laser; harmonic generation; high-order rotational lines; hydrogen; hydrogen pressure; laser polarization; line broadening; near-infrared; pulsewidth; pump beam; rotational Raman lines; seed beam; self-focusing; self-phase modulation; spectral region; stimulated Raman scattering; white light continuum; Frequency conversion; Hydrogen; Laser beams; Optical modulation; Optical polarization; Optical pulse generation; Pulse modulation; Raman scattering; Space vector pulse width modulation; Stimulated emission;
Journal_Title :
Quantum Electronics, IEEE Journal of
