Accession Number : AD0866935

Title :   Raman Scattering in Semiconductors.

Descriptive Note : Final rept. 1 Oct 67-30 Apr 69,

Corporate Author : YALE UNIV NEW HAVEN CT DUNHAM LAB

Personal Author(s) : Chang, Richard K. ; Ralston, James M.

Report Date : SEP 1969

Pagination or Media Count : 60

Abstract : The report concerns the initial stages of an investigation into stimulated Raman effect on mixed crystals. Spontaneous Raman studies were conducted first to determine the lattice vibrations of the mixed crystals and of other semiconductors. The Raman linewidths of the L0 and T0 modes for GaAs and that of the triply degenerate mode for Si were measured from 10 degrees K to 475 degrees K. A pronounced increase in the Si Raman scattering, radiated by a CW YAG laser, was observed when the sample temperature was cooled. Such increase is attributed to resonance effects between the laser photon-energy and the indirect energy gap of Si. Prior to obtaining stimulated Raman oscillators in semiconductors, the effects of multiphoton absorption was studied. Stepwise multiphoton absorption in Si was observed from 146 - 452 degrees K. The use of this multiphoton absorption as an optical limiter and pulse stretcher when such nonlinear absorber is inserted within the laser cavity is discussed. Stimulated Raman Oscillations in Si have been observed at 77 degrees K with a Q-switched Nd:YAG laser. (Author)

Descriptors :   (*LASERS, TUNING DEVICES), (*SEMICONDUCTORS, RAMAN SPECTROSCOPY), SOLID SOLUTIONS, CADMIUM SULFIDES, CADMIUM SELENIDES, GALLIUM ARSENIDES, SILICON, CRYOGENICS.

Subject Categories : Lasers and Masers
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE