Single Crystal Piezoelectric Actuators for Membrane Optics

Single crystal relaxor piezoelectrics based on Pb(Mg1/3Nb2/3)1-xTixO3 will be investigated for use as actuator plates with an interdigitated electrode pattern providing nearly ?33? mode actuation in the direction of the plate?s longest dimension and as ?31? mode devices driven without electrical connections using an electron beam. Given the large strains (>0.5%), low hysteresis, and good cryogenic performance of single crystal relaxors, the lightweight actuator designs proposed are expected to be ideal candidates for active control of membrane optical systems. Potential adaptive optics designs include edge controlled mirrors with interdigitated electrode actuators located between the reflective membrane and the mirror frame and integrated mirrors consisting of ?31? mode crystal plates bonded to a membrane mirror and driven without direct voltage contacts using an electron beam. Strain amplification through use of bending mode actuators (bimorphs and unimorphs) will also be investigated. By the conclusion of the Phase I program the feasibility of lightweight crystal actuators for adaptive optics will be demonstrated with direct strain measurements from 300 to 20K. Actuator and optics product development will take place in Phase II.