Accession Number : AD0841118

Title :   LASER SPECTRAL CONTROL TECHNIQUES.

Descriptive Note : Final engineering rept. 17 Feb 67-17 Feb 68,

Corporate Author : SYLVANIA ELECTRONIC SYSTEMS-WEST MOUNTAIN VIEW CA

Personal Author(s) : Osterink, L. M. ; Foster, J. D.

Report Date : SEP 1968

Pagination or Media Count : 210

Abstract : A mode-locked cs Nd:YAG laser was developed whose output was a pulse train with 28 picosecond pulsewidths and a 2.6 nanosecond pulse repetition frequency. The modes were locked using a LiNbO3 intra-cavity phase modulator. Over one watt of average mode-locked power in the TEMoo mode was obtained. This laser was frequency stabilized by comparing the phase of the output pulse train to that of the modulator drive signal. A shift in pulse phase occurs when the laser c/2L frequency differs from the modulation frequency. By stabilizing the modulation frequency to a frequency standard, one can use the pulse phase shift discriminant to stabilize the cavity length. A novel optical means of detecting the phase shift of the pulse was used and is described. The thermal properties of the Nd:YAG rod were studied in detail. Measurements of the thermally-induced focal length, thermal strain birefringence, dn/dT, and the thermal expansion coefficient of Nd:YAG are presented. The thermal properties are related to achieving optimum transverse mode control in the laser. (Author)

Descriptors :   (*LASERS, PHASE LOCKED SYSTEMS), (*OPTICAL RADAR, LASERS), FREQUENCY, STABILIZATION SYSTEMS, NEODYMIUM, GARNET, OPTICAL PUMPING, MODULATION, PULSES, CAVITY RESONATORS, THERMAL PROPERTIES.

Subject Categories : Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE