Switchable optical image adder/subtractor.
We demonstrate a switchable, parallel optical image adder/subtractor, using a Michelson interferometer configured with a phase-conjugating mirror. With the path difference of the interferometer legs within the coherence length of the laser, coherent image subtraction is obtained. By electronically switching the beam in one of the legs in the interferometer into an extra length, beyond the coherence length of the laser, incoherent image addition is performed. Two simple experiments showing the switching characteristics and the arithmetic operations are described. This kind of device should find applications in image processing and optical computing.
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Hengst
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Roh