840-Hz Nd:YAG Laser Source of Sodium Resonance Radiation
Final rept. Jan 1989-Mar 1991
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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A 20-W average power laser source of sodium resonance radiation has been developed and delivered to the Air Force Phillips Laboratory to generate a fluorescence spot in the earths mesospheric sodium layer for atmospheric adaptive optics applications. The sodium resonance radiation was generated by sum-frequency mixing 1.06- and 1.32-UM NdYAG laser radiation in a lithium triborate crystal. The pulsed NdYAG lasers operated with a repetition rate of 840 Hz and pulse lengths of about 100 us. The sum radiation was resonant with the sodium D 2 transition and generated with an average mixing efficiency of 30. The lasers were mode-locked with a controlled pulse width that provided a spectrally broadened output matched to the 3-GHz Doppler-broadened absorption width of mesospheric sodium. Nd YAG lasers, sodium resonance radiation, sum- frequency mixing, mesospheric sodium, lithium triborate, adaptive optics.
- Atmospheric Physics
- Lasers and Masers