Abstract: Provided is an optical apparatus comprising a hygroscopic optical crystal and a coating on at least a portion of the surface of the hygroscopic optical crystal, wherein the coating is non-porous and configured to prevent migration of water and/or oxygen and/or moisture therethrough.

Abstract: An outdoor, battery powered digital camera includes a passive infrared motion detector that allows the camera to be left unattended, as the detector automatically triggers the camera to take a picture upon sensing the presence of a moving animal. To prolong the life of the battery, the camera goes into a power-saving sleep mode between pictures. To enable the camera to instantly take a picture upon suddenly being awakened by the motion detector, the exposure setting of the camera is periodically checked, adjusted and stored so that the camera can use that fairly recent exposure setting, or one near it, to take an instant picture rather than wasting excessive time adjusting the exposure when the animal first appears. In some cases, the camera is used in conjunction with picture management software.

Abstract: An acousto-optic modulator includes a (100), (010) or (001) single crystal silicon acousto-optic interaction medium, and at least one transducer for emitting an acoustic wave attached to the single crystal. The transducer has a first electrode layer disposed on one side and a second electrode layer disposed on its other side. The transducer is aligned to the single crystal so that the direction of acoustic propagation in the silicon crystal is substantially along the (100), (010) or (001) direction. A q-switched laser includes a modulator according to the invention.

Abstract: An acousto-optic modulator includes a (100), (010) or (001) single crystal silicon acousto-optic interaction medium, and at least one transducer for emitting an acoustic wave attached to the single crystal. The transducer has a first electrode layer disposed on one side and a second electrode layer disposed on its other side. The transducer is aligned to the single crystal so that the direction of acoustic propagation in the silicon crystal is substantially along the (100), (010) or (001) direction. A q-switched laser includes a modulator according to the invention.