PRIZ optical modulator

Principle operating

PRIZ is optically addressed spatial light modulator (OASLM) with photorefractive Bi12SiO20 (BSO), Bi12GeO20 (BGO) crystals, which crystallographic orientation is cut-111 or cut-110 of polished sides S1, S2 in contrast to PROM devices where longitudinal Pockels effect is used for crystal with cut-100 orientation.  Photorefractive BSO, BGO crystals also used simultaneously as electro-optic and photoconductive mediums.  A photosensitive layer detects the writing beam intensity distribution and induces the electron charge distribution inside the crystal. Construction of PRIZ modulator is the same like PROM device: external electric field is applied also along light direction into crystal, but optical modulation is a result of transverse electro-optic effect, provided by internal electric field into photorefractive crystal. The internal electric field is generated both with gradient of writing illumination light in the plane of polished sides of crystal and with applied external electric field. In result of this internal transverse PRIZ modulation it is possible to obtain image contour which associated with intensity interface of writing image. It is characteristic property of PRIZ optical modulator, which was developed by Ioffe Institute. The readout can be realized using a coherent light beam either in transmission or in reflection mode. New type PRIZ modulator can be developed, manufactured and supplied for customized applications for selected spectral ranges and incident radiation powers. 

Construction of PRIZ optical modulator

Active areaØ 25 mm
Electro-optic mediumBGO crystal with aperture 30X30 mm
Thickness of crystal0.5 – 1.5 mm
Electrodes  S1: ITO     S2: ITO
Optical internal structure ITO//BGO//ITO
PackagePlastic 50X70X30 with connector

The basic features of PRIZ in comparison with PROM devices

  • Dynamic image selection
  • Contouring of image
  • Sector filtering of image
  • Low noises
  • Higher resolution

BGO crystals 30X30X1 mm for PRIZ optical modulators