HOLOGRAPHIC COATINGS FOR TELESCOPES

DURING THE PAST YEAR, PHYSICAL OPTICS CORPORATION (POC) HAS BEEN SUCCESSFUL IN FABRICATING HOLOGRAPHIC RUGATE STRUCTURESFOR THE UV, VISIBLE, AND VERY NEAR IR REGIONS OF THE SPECTRUM. THESE HOLOGRAPHIC MIRRORS DEMONSTRATED LASER DAMAGE THRESHOLDS WHICH WERE 5 TIMES BETTER THAN THE BEST DIELECTRIC MULTILAYER COATINGS, WITH REFLECTIVITIES IN EXCESS OF 99.9%. THIS RESEARCH PROJECT PROPOSES TO EXTEND THIS HOLOGRAPHIC RUGATE TECHNOLOGY TO THE REGION FROM 1 MUM TO 3 MUM. THE HOLOGRAPHIC RECORDING PROCESS FOR THE IR REGION SHOULD ALSO YIELD ULTRA HIGH DAMAGE THRESHOLDS AND BEEASILY SCALABLE TO VERY LARGE OPTICS. THE HOLOGRAPHIC PROCESSES EMPLOYED USE LOW TEMPERATURE DEPOSITION METHODS AND AN INTEGRATION OF HOLOGRAPHIC COATINGS WITH GRATINGS. THESE GRATINGS CAN BE USED AS BEAM SAMPLERS OR OUTPUT COUPLERS. THE POTENTIAL FOR A SIMPLE FABRICATION PROCESS, LOW ABSORPTION CHARACTERISTICS OF THE RECORDING MEDIUM, AND A DEMONSTRATED RADIATION HARDNESS MAKE POC'S COATING PROCESSAN IDEAL NEW TECHNOLOGY FOR CIVILIAN AND MILITARY APPLICATIONS. POC'S APPROACH WILL GREATLY REDUCE STRUCTURALWEIGHT, THERMAL LOAD AND COST COMPARED TO EXISTING COATING TECHNOLOGIES SINCE IT CAN BE APPLIED TO LIGHT-WEIGHT SUBSTRATES SUCH AS GRAPHIC-EPOXY, MYLAR, ALUMINUM, AND ULTRA-THIN GLASS. MOREOVER, INITIAL EXPERIMENTAL RESULTS HAVE DEMONSTRATED THAT THE COATING HAS NO DEGASSING PROBLEM.