Novel theoretical aspects on photorefractive ultrasonic detection and implementation of a sensor with an optimum sensitivity
作者:
Louis-Anne de Montmorillon,
Philippe Delaye,
Jean-Claude Launay,
Ge´rald Roosen,
期刊:
Journal of Applied Physics
(AIP Available online 1997)
卷期:
Volume 82,
issue 12
页码: 5913-5922
ISSN:0021-8979
年代: 1997
DOI:10.1063/1.366492
出版商: AIP
数据来源: AIP
摘要:
We here expose theoretical and experimental results on homodyne detection using near-infrared laser sources, at 1.06, 1.32, and 1.55 &mgr;m wavelengths. The used photorefractive crystals are two large size CdZnTe:V samples. With speckled beams such as the ones scattered by diffusive objects, we reach a detection limit which, at 1.55 &mgr;m, is only 1.6 times above the one obtained with plane waves in a classical interferometer and only 2 and 2.2 times above at 1.32 and 1.06 &mgr;m, respectively. It is then demonstrated that the electron–hole competition, which varies enormously between these three wavelengths and gives a nearly zero two-wave-mixing gain at 1.32 &mgr;m, does not influence the sensitivity of the system. Moreover, we show that the frequency cutoff of the system is four times higher in the attenuation regime than in the amplification one. ©1997 American Institute of Physics.
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