Zero-Power Gain Measurements in a CW HF Laser Using a Pulsed-Probe Laser.
Rept. for Mar-Jun 71,
AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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Zero-power gain measurements in a supersonic diffusion-type CW HF laser are made using a pulse HF probe laser. A peak zero-power gain of 10 cm is measured on a P23 vibrational-rotational transition and 7 cm on a P16 transition for flow rates corresponding to 1.8 kW of closed-cavity power. The measured streamwise gain distributions of the P25 and P16 transistions were compared with the theory of King, et al., and the values of the peak gain agreed to within 50. The variation of zero-power gain with rotational quantum number J fits a simple rotational equilibrium model indicating increasing rotational temperatures with increasing distance x from the nozzle exit plane. The model also indicates a total inversion for x 0.2 in. for the P2J transitions and a partial inversion further downstream. The results indicate large amplitudes about 50 temporal-gain fluctuations in the active medium and the measured gain in a time-averaged value. Author
- Lasers and Masers