CHARACTERIZATION AND OPTIMIZATION OF AN ELECTRO-OPTIC IMAGING DEVICE FOR REAL-TIME MAP PROFILING

摘要

The operation of an electro-optic image modulator and storage device for use in real-time optical processing systems is described. Major emphasis was placed in optimizing the device performance by proper selection of design and operating parameters. The Pockels Read-Out Optical Modulator (PROM) is used to provide temporary storage of an image that can be read into the PROM either sequentially from a laser or CRT scanner or in parallel from a transparency. The PROM is constructed from a thin slice of bismuth silicon oxide, a cubic crystal exhibiting the Pockels effect, photoconductivity when illuminated with blue light, and resistivity sufficient to allow up to 2 hours of charge storage. The crystal slice is oriented normal to (100), polished flat, and coated with an insulating layer of parylene. A dichroic layer, reflecting red light but transmitting blue, is sometimes deposited on one side of the crystal before it is coated with parylene. In the operation of the device, an electric field is first stored in the crystal by inducing surface charges at the crystal-parylene interfaces. The stored image can then be read out by incoherent light or by a laser for coherent optical processing.