Optic Bistable Device with Low Threshold-Intensity (mw/cm2)

BRIMROSE CORPORATION PROPOSES TO INVESTIGATE, DESIGN AND DEMONSTRATE A NOVEL OPTICAL BISTABLE DEVICE WITH A THRESHOLD OPTICAL INTENSITY SEVERAL ORDERS OF MAGNITUDE LOWER THAN THE CONVENTIONAL DEVICES. THIS DEVICE WILL OPERATE AT ROOM TEMPERATURE USING A LOW POWER CW LASER. ADVANTAGE OF SUCH A DEVICE WILL SIGNIFICANTLY FACILITATE THE NUMBER OF PROCESSING OPERATIONS IN OPTICAL COMPUTING AND SIGNAL PROCESSING. TO DATE, IN ALMOST ALL BISTABLE DEVICES, THE NONLINEAR RESPONSE IS PROPORTIONAL TO THE INCIDENT OPTICAL INTENSITY. THE THRESHOLD INTENSITIES OF THE OPTICAL BISTABLE DEVICES DEMONSTRATED SO FAR IS ABOUT 10(8) W/CM2. IN PHOTOREFRACTIVE MATERIALS, THE NONLINEAR RESPONSE DEPENDS ON THE MODULATION INDEX RATHER THAN THE INTENSITY. THE PROPOSED DEVICE, THEREFORE, DRASTICALLY REDUCES THE THRESHOLD INTENSITY OF THE PROPOSED DEVICE TO THE MW/CM2 RANGE. THIS DEVICE WILL BE FABRICATED FROM A PHOTOREFRACTIVE (PR) SEMICONDUCTOR MATERIAL, ZnTe:V, WHICH HAS BEEN WORKED ON FOR OVER FOUR YEARS AND BRIMROSE IS THE ONLY MANUFACTURER IN THE WORLD. IT HAS THE PHOTOREFRACTIVE SENSITIVITY IN THE WAVELENGTH RANGE 0.6 um TO 1.5 um WHICH COMPATIBLE WITH EXISTING LOW POWER SEMICONDUCTOR LASER WAVELENGTHS. THE DEVICE HAS A SIMPLE CONCEPT AND THE DESIGN. A THIN LAYER OF PHOTOREFRACTIVE ZnTe:V IS SANDWICHED BETWEEN TWO SEMI-INFINITE DIELCTRICS, THE SUBSTRATE AND THE COVER. AN OPTICAL WAVE IS INCIDENT FROM THE COVER SIDE ONTO THE COVER-PR INTERFACE. THE TRANSMITTED WAVE TRAVERSES THE PR REGION AND THEN IS PARTIALLY REFLECTED BACK INTO THE PR MATERIAL. DUE TO THE PHOTOREFRACTIVE NONLINEARITY, THE TWO WAVES INSIDE THE PR MATERIAL EXPERIENCE TWO-WAVE COUPLING. THIS IS THE NONLINEAR MECHANISM OF THIS BISTABLE DEVICE.