Pockels Readout Optical Modulator
Principle operating
PROM is a typical optically addressed spatial light modulator (OASLM) with photorefractive Bi12SiO20 (BSO), Bi12GeO20 (BGO) crystals used simultaneously as electro-optic and photoconductive mediums. The basic principle of PROM type modulators is the following. A photosensitive layer detects the writing beam intensity distribution and induces the electron charge distribution inside the crystal. Optical properties of the crystal occur to modify as a function of photo-induced electron charges or photo voltage. The applied electric bias forces to drift the mobile carriers to the crystal / dielectric interface until the electric field in the crystal was cancelled. The photo-induced space charge in BSO, BGO crystals modulates the birefringence through the electro-optic longitudinal Pockels effect. The readout can be realized using a coherent light beam either in transmission or in reflection mode. A new type PROM modulator can be developed, manufactured and supplied for customized applications for selected spectral ranges and incident radiation powers.
Technical characteristics of PROM-020 series
Active area | Ø 20 mm |
Electro-optic medium | BGO crystal |
Thickness of crystal | 0.2 – 2 mm |
Electrodes | S1: Al metal or ITO S2: ITO |
Optical internal structure | Al (or ITO)/BGO/ITO |
Package | Plastic 50X70X30 With connector |
The basic advantages of PROM devices on basis of Bi12GeO20 (BGO), Bi12SiO20 (BSO)
- Opportunity to read efficiently UV, X — ray photons with simple red laser line writing/detection optical system
- BSO and BGO are simultaneously electro-optic and photoconductive crystals
Applications of PROM modulators
- Incoherent image enhancement
- Image or signal correlation
- Real-time spatial filter generation
- And two-dimensional logical operations
- X-ray image detection
PROM-020 modulator in full assembling
