METHOD FOR OPTICAL TOMOGRAPHY OF PHOTOSENSITIVE MATERIALS Russian patent published in 2009 - IPC G01N21/45 

FIELD: physics; optics.

SUBSTANCE: invention relates to methods of investigating properties of materials, mainly meant for use in three-dimensional holographic recording information. Bulk photosensitive material is placed in the interference zone of two intersecting collimated laser light beams. Depth dimensions of the zone are larger than the thickness of the material. Each beam is formed as a result of diffraction of light on a progressive ultrasound wave in an acoustooptical deflector. A three-dimensional (volume) holographic grating is recorded using a stroboscope. For layer by layer measurement of parametres of the recorded holographic grating, both beams are simultaneously scanned at an angle. The Doppler shift of the frequency of light of each beam is varied linearly with time. The Doppler shift of frequency of one beam with respect to the other beam is kept constant during the scanning cycle, forming a scanning interference grating with speed of motion which varies on the depth of the material. The scanning process is repeated at different angles of intersection of the beams.

EFFECT: high-speed scanning, extreme resolution on depth and increased sensitivity of measurement.

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