Degenerate four-wave mixing of c-w h-f laser beams in h-f absorption cell. Technical report

Technical Report · Mon Aug 06 00:00:00 EDT 1990

OSTI ID:5688513

Mirels, H; Coffer, J G; Bernard, J M; Chodzko, R A

Phase conjugation of a cw hydrogen fluoride (HF) laser beam has been investigated experimentally and theoretically using resonant degenerate four-wave mixing (DFWM) in an HF gas absorption cell. A single-line single-mode HF laser, operating on P1(8), P1(9),or P1(10) transitions, provided total (forward plus backward) pump beam intensities of 130, 600, and 400 W/sq. cm., respectively, in the HF absorption cell. A probe beam intensity of the order of 10 W/sq. cm. was also provided. Conjugate reflection of the probe beam was investigated as a function of gas cell pressure and as a function of frequency detuning from line center. The variation of reflectivity with gas cell pressure at fixed laser beam intensity indicated a peak reflectivity of the order of .0001 at pressures from 2 to 4 Torr. Measurement of conjugate beam intensity, as a function of frequency detuning from the line center,provided a signal with a full width at half maximum (FWHM) of about 30 MHz. The latter is of the order of the homogeneous width, for HF at the test pressure, and may be compared to the Doppler width delta nu sub d = 300 MHz for the medium. An Analytical model is presented which provides theoretical estimates for the variation of reflectivity with pressure. Effects of diffusion, thermal conduction, pump depletion, and a nonuniform (Gaussian) profile are considered. Theoretical estimates for peak reflectivity agree with experiments to within a factor of about 2.

• Research Organization: Aerospace Corp., El Segundo, CA (USA). Laboratory Operations
• OSTI ID: 5688513
• Report Number(s): AD-A-230183/6/XAB; TR-0089(4930-06)-3
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
GAS LASERS
LASER RADIATION
FREQUENCY MIXING
ABSORPTION
GASES
HYDROGEN
MATHEMATICAL MODELS
NONLINEAR OPTICS
PROBES
PUMPS
REFLECTION
REFLECTIVITY
THERMAL CONDUCTIVITY
TUNING
VARIATIONS
WIDTH
DIMENSIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
LASERS
NONMETALS
OPTICAL PROPERTIES
OPTICS
PHYSICAL PROPERTIES
RADIATIONS
SURFACE PROPERTIES
THERMODYNAMIC PROPERTIES
426002* - Engineering- Lasers & Masers- (1990-)