Accession Number : AD0907115

Title :   Frequency-Doubled, Mode-Locked Nd:YAG Laser.

Descriptive Note : Final technical rept.,

Corporate Author : UNITED AIRCRAFT RESEARCH LABS EAST HARTFORD CT

Personal Author(s) : Clobes, Arnold R.

Report Date : DEC 1972

Pagination or Media Count : 80

Abstract : The objective of the work reported herein is to achieve stable mode-locked, second harmonic power output from a Nd:YAG laser. Particular emphasis is placed on amplitude stability and on conversion efficiency. The experimental results of this program are 200 mW of 0.53 micron mode-locked power output at a PRF of 500 MHz. The amplitude fluctuations are + or - 4%. The intracavity barium sodium niobate crystal, used as both the second harmonic generator and mode-lock modulator, was driven at 250 MHz. Stability control techniques successfully demonstrated include: (1) cladding of the laser rod; (2) amplitude equalization of the output pulse train; (3) maintaining the relative frequency difference between the modulator drive and the cavity c/2L frequency within narrow limits by use of a phase-lock loop; (4) series regulation of the lamp current and the use of ballast resistors; and (5) maintaining the nonlinear crystal at the phase-match temperature by closed-loop control of the oven temperature. Thermal effects in the banana crystal arising from absorption of the fundamental wavelength radiation were found to limit the amplitude stability of the laser output. The same effects distort the 0.53 micron far-field beam profile and reduce the conversion efficiency.

Descriptors :   (*LASERS, FREQUENCY CONVERTERS), INFRARED LASERS, NEODYMIUM, STABILITY, PHASE LOCKED SYSTEMS, NIOBATES, BARIUM COMPOUNDS, SODIUM COMPOUNDS, FOCUSING, THERMAL PROPERTIES, HARMONIC GENERATORS, EFFICIENCY, OPTICAL COMMUNICATIONS, INTERFEROMETERS, SPACE COMMUNICATIONS, SPACEBORNE.

Subject Categories : Lasers and Masers
      Non-radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE