Study on Optical Servosystem : Contribution to Optical Actuator

This paper deals with a new concept of an optical servosystem and presents an experimental analysis on photostrictive ceramics for use as an optical actuator in the optical servosystem. The optical servosystem proposed here is characterized by introduction of an optical actuator into the system. PLZT ceramics is used as an optical actuator which is directly driven by light irradiation. The photostrictive effect in the PLZT ceramics produced from the superposition of the photovoltaic effect and the piezoelectric effect is experimentally evaluated from the viewpoint of its applicability to an optical actuator. The experimental results show that the PLZT ceramics generates a mechanical strain as large as conventional PZT ceramics but at a very slow dynamic response of about 40 seconds. The slow dynamic response is attributed to the time lag in the photovoltaic effect.