PHASE CONJUGATE WAVEFRONT CORRECTION OF LASER TRANSMISSION THROUGH THE ATMOSPHERE

FOR OPTICAL OR INFRARED LASER RADIATION TRANSMITTED THROUGH THE EARTH'S ATMOSPHERE, ONE CAN BUILD AN IMAGING SYSTEM IN WHICH NONLINEAR OPTICAL PHASE CONJUGATION IS USED TO CORRECT FOR WAVEFRONT DEGRADATION INDUCED BY ATMOSPHERIC TURBULENCE. TWO TYPES OF SUCH SYSTEMS ARE POSSIBLE. THE SIMPLER IS DESIGNED FOR TWO-WAY TRANSMISSION OF AN IMAGE, THE MORE DIFFICULT IS DESIGN FOR ONE-WAY TRANSMISSION OF AN IMAGE. THE SUCCESSFUL OPERATION OF BOTH DEVICES DEPENDS IN PART ON THE CHOICE OF CONJUGATE MATERIAL AND THE TYPE OF NONLINEAR INTERACTION EMPLOYED. THE EFFECTIVENESS OF THE ONE-WAY DEVICE IS ALSO UNIQUELY DEPENDENT ON THE DESIGN OF CONVENTIONAL IMAGING OPTICS AND THE SPATIAL BANDWIDTH OF THE TRANSMITTED INFORMATION. THIS PROPOSAL ADDRESSES THE CHOICE OF CONJUGATOR MEDIUM FOR COMPENSATED TRANSMISSION OF IMAGES, THE APPROPRIATE LASER SOURCE, AND IMAGING OPTICS DESIGN. THE CONJUGATOR TYPE PROPOSED WILL BE ONE OF A NUMBER OF AVAILABLE INFRARED-PHOTOREFRACTIVE SEMICONDUCTORS, SUCH AS DOPED INP, GAAS, OR CDTE.