Generation of 16 micron radiation using stimulated rotational Raman scattering in hydrogen

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6054427

Trutna, Jr, W R

Stimulated rotational Raman scattering has been successfully used to frequency shift a CO/sub 2/ TEA laser from 10.6 ..mu..m to 16.95 ..mu..m. Since Raman gain in para-H/sub 2/ at 10.6 ..mu..m is quite low, two techniques were used to lower the CO/sub 2/ laser power requirements. First a 25 transit Raman cell was constructed, which maintains a high pump intensity over a long distance, to maximize Raman gain. Second, four wave mixing was utilized to generate a 16.95 ..mu..m signal at the kilowatt level to inject into the Raman amplifier. Since the Raman signal normally builds up from noise (approx. 10/sup -12/ watts), pre-injection with four wave mixing significantly lowers the Raman gain requirements. With a 2 J, 70 nsec CO/sub 2/ laser pulse, 40 mJ of 16.95 ..mu..m energy was generated in an 8 nsec pulse. The 50 mJ energy corresponds to a peak photon conversion efficiency of 40%. By tuning the CO/sub 2/ laser, it should be possible to generate frequencies useful for uranium isotope separation. Since the CO/sub 2/ laser tends to oscillate at many axial mode frequencies, a theoretical study was made to determine the dependence of Raman gain and Stokes bandwidth upon the pump laser bandwidth. The results were experimentally verified using a variable bandwidth Nd:YAG laser at 1.06 ..mu..m. The final chapter contains the results of experiments with an antiresonant ring resonator operated with a low pressure pulsed CO/sub 2/ laser. A new method of cavity dumping based upon the antiresonant ring and an electrooptic phase modulator was demonstrated.

• Research Organization: Stanford Univ., CA (USA)
• OSTI ID: 6054427
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
AMPLIFICATION
CARBON DIOXIDE LASERS
CONTROL
DATA
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
EXPERIMENTAL DATA
FREQUENCY CONTROL
GAIN
GAS LASERS
HYDROGEN
INFORMATION
ISOTOPE SEPARATION
LASER ISOTOPE SEPARATION
LASERS
NONMETALS
NUMERICAL DATA
OSCILLATIONS
RAMAN EFFECT
RESONATORS
SEPARATION PROCESSES
TUNING