Application of PLZT electro-optical shutter to diaphragm of visible and mid-infrared cameras

摘要

Abstract:Pb$-0.9$/La$-0.09$/(Zr$-0.65$/,Ti$-0.35$/)$-0.9775$/O$-3$/9/65/35) commonly used as an electro-optical shutterexhibits large phase retardation with low appliedvoltage. This shutter features as follows; (1) highshutter speed, (2) wide optical transmittance, and (3)high optical density in 'OFF'-state. If the shutter isapplied to a diaphragm of video-camera, it couldprotect its sensor from intense lights. We have testedthe basic characteristics of the PLZT electro-opticalshutter and resolved power of imaging. The ratio ofoptical transmittance at 'ON' and 'OFF'-states was 1.1$MUL 10$+3$/. The response time of the PLZT shutterfrom 'ON'-state to 'OFF'-state was 10 micro second. MTFreduction when putting the PLZT shutter in from of thevisible video- camera lens has been observed only with12 percent at a spatial frequency of 38 cycles/mm whichare sensor resolution of the video-camera. Moreover, wetook the visible image of the Si-CCD video-camera. TheHe-Ne laser ghost image was observed at 'ON'-state. Onthe contrary, the ghost image was totally shut out at'OFF'-state. From these teste, it has been found thatthe PLZT shutter is useful for the diaphragm of thevisible video-camera. The measured opticaltransmittance of PLZT wafer with no antireflectioncoating was 78 percent over the range from 2 to 6microns. !1