Accession Number : AD0766415

Title :   Zero-Power Gain Measurements in a CW HF Laser Using a Pulsed-Probe Laser.

Descriptive Note : Rept. for Mar-Jun 71,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Chodzko,Richard A. ; Spencer,Donald J. ; Mirels,Harold

Report Date : 20 SEP 1973

Pagination or Media Count : 28

Abstract : 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 P2(3) vibrational-rotational transition and 7% cm on a P1(6) transition for flow rates corresponding to 1.8 kW of closed-cavity power. The measured streamwise gain distributions of the P2(5) and P1(6) 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 P2(J) 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)

Descriptors :   (*GAS LASERS, GAIN), SUPERSONIC FLOW, ELECTRON TRANSITIONS

Subject Categories : Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE