| 摘要 |
An all-optical, self-aligning, holographic phase modulation and motion sensing apparatus includes a crystal exhibiting a zero electric field photorefractive effect, a phase modulation or vibration source or mechanism, a source of coherent optical radiation, beam splitting and directing optics, and at least one optical radiation detector. The output from the optical radiation source is split into separate beams, one or all of which are phase modulated. The beams are directed through the crystal exhibiting a zero electric field photorefractive effect, and the resultant transmitted beams are detected by an optical radiation detector to provide a measurement of the phase modulation of the beams. The sensor functions in the absence of an electric field because of the unique characteristic of the crystal exhibiting the zero electric field photorefractive effect whereby if either the phase of the crystal's index grating or of the interfering beams is modulated with a phase change very much less than pi /2, the intensity of the beam transmitted through the crystal varies linearly with the modulation. Such linear modulation allows crystals exhibiting the zero electric field photorefractive effect to remotely sense phase modulations or vibrations of any type in the absence of electrical signals in the vicinity of the sensor.
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