Optimization and Reduced Print Thru in HEL Deformable Mirrors

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.