SBIR-STTR Award

Several possible material and design changes to improve HEL deformable mirrors will be discussed. The principles will apply to Air Force ACDM and BCDM mirrors and to other HEL mirror designs. Simple changes to conventional mirrors and a new mounting technique are evaluated first using highly efficient finite element thermal analysis. Material changes including substitution of a low expansion, low thermal conductivity, lightweight, relatively inexpensive faceplate for the current high expansion coefficient, transparent silicon faceplate and development of a high thermal conductivity, opaque faceplate similar to silicon but having a low expansion coefficient are considered. High thermal conductivity low expansion coefficient mirrors have the smallest mirror distortion coefficient theoretically. The last concept could be developed and the other ideas demonstrated experimentally in an SBIR Phase II project.

Keywords:
Adaptive Opic Hel Mirror Design, Low Visible Scattered Light Mirrors, New Material Combinations For Hel Mirrors, Hel Mirror Actuators, Low Distortion Hel Mirrors, Iodine Laser

The objective of this program is to develop adaptive optic laser mirrors which exhibit minimum distortion when irradiated with high power laser flux. Two approaches will be tried utilizing two sets of previously selected candidate materials. Results will indicate how to significantly improve the performance of the Air Force ACDM and BCDM laser mirrors as well as to improve the performance of laser mirrors in general which are exposed to high powers. Actuator spacing will be 3.34 cm with provision for 1.67 cm spacing to be used. A novel actuator design and mounting will be used which calculations indicate will both significantly decrease the magnitude and increase the uniformity of the thermal heating of the mirrors. One approximately 10 inch diameter subscale adaptive optic mirror of each set of materials will be fabricated, polished, analyzed, laser damage tested at the Boeing Kirtland AFB iodine laser damage test facility and delivered in this Phase II program.

Keywords:
Thermally Stable Graphite Materials, Thermally Stable Ceramic Materials, Thermally Stable Actuators, Adaptive Optic Mirrors, Astronomical Mirrors, Las