Advanced Actuator Concepts for High Precision Deformable Mirrors

TRS Technologies proposes to develop a variety of single crystal actuators for adaptive optics deformable mirrors. Single crystal piezoelectric actuators are proposed as a means of increasing actuator authority while maintaining strain precision for adaptive optics deformable mirrors used in future space observatory missions. Single crystals based on PZN-PT or PMN-PT represent a revolutionary advance in piezoelectric actuator technology. These materials exhibit 5 to 10 times the strain of conventional ceramic piezoelectrics with equivalent deliverable force. Therefore, they offer a much broader design space for adaptive optics systems than is currently available with ceramic actuators, electric motors or magnetic devices. The attributes of single crystals relevant to adaptive optics include: piezoelectric coefficients > 2000 pm/V and field induced strains > 0.5%, blocking forces equivalent to conventional piezoelectric and electrostrictive ceramic, very low strain-electric field hysteresis for high strain precision, much broader operating temperature range than electrostrictive PMN ceramic, very good cryogenic performance, and very high transverse piezoelectric coefficients (d32 better than -1600 pm/V). In the Phase I program TRS will measure the performance of both stack and flextensional-type actuators and SRS will model the impact of incorporating such actuators into state-of-the-art deformable mirror designs.