Accession Number : AD0800395

Title :   LASER MATERIAL (SPECTROSCOPY).

Descriptive Note : Semiannual rept. no. 3, 15 Dec 65-15 Jun 66,

Corporate Author : STANFORD UNIV CA MICROWAVE LAB

Personal Author(s) : Siegman, A. E.

Report Date : SEP 1966

Pagination or Media Count : 64

Abstract : A new method has been proposed and analyzed for measuring the short-term frequency and phase fluctuations of a laser oscillator, by heterodyning one laser with two other similar lasers and correlating the outputs from two i-f discriminators. Experimental measurements of laser frequency fluctuations and spectral characteristics are now in progress by heterodyning two lasers, as a preliminary to implementing the proposed three-laser method. Two stable He-Ne 6328A lasers located in an isolated vault are presently being heterodyned together in order to test the various components and techniques needed for the three-laser measurement. The lasers and the photodetection, frequency discrimination, and AFC circuitry have all been assembled and are operating very satisfactorily, while the remaining signal processing circuitry is being developed. Preliminary measurements of the FM spectra and the mechanical resonances of the lasers have been made, and these measurements are continuing. External-mirror operation of a Nd:YAW cw laser has also been achieved. Further spectral analyses and other studies of this type of laser will now proceed, using a scanning Fabry-Perot interferometer as well as heterodyne methods. Various analyses of the threshold and other properties of this type of laser are also in progress. (Author)

Descriptors :   (*LASERS, MATERIALS), EXCITATION, OPTICAL PUMPING, FREQUENCY MODULATION, NEODYMIUM, YTTRIUM, ALUMINUM, GARNET, CRYSTALS, HELIUM, CIRCUITS, CORRELATION TECHNIQUES, INTERFEROMETERS, DISCRIMINATORS, OSCILLATORS, INTERMEDIATE FREQUENCIES.

Subject Categories : Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE