PHONON INTERACTIONS IN CRYSTALS.
Quarterly progress rept. no. 2, 15 Aug-14 Nov 63,
IBM THOMAS J WATSON RESEARCH CENTER YORKTOWN HEIGHTS NY
Pagination or Media Count:
From the high efficiency of the parametric upconversion process previously reported, it appeared that parametric amplification of X-band acoustic signals should be observable. Such parametric down-conversion and amplification has now been achieved. A pump signal at 16.45 Gcsec was introduced into a magnesium oxide rod, and a gain of one dbcm was observed at frequencies near 8.5 Gcsec. This gain was limited only by the amount of pump power that the 16.45 Gcsec cavity would accept without breakdown. The upconversion process was verified by bringing the harmonic signal out of the cryostat in the form of electromagnetic energy and directly detecting it. During this investigation, an additional new harmonic generation process has been observed. This process takes place at the surface of the quartz transducer and is probably caused by a polarization at the surface proportional to the square of the elctric field. This process does not depend on the piezoelectricity of the quartz and should be present in all materials in varying degrees. Author