Theoretical and experimental study of optothermal expansion and optothermal microactuator

A new type of microactuators based on optothermal (OT) expansion is introduced. The mechanism of the OT expansion is theoretically analyzed, and comprehensive models for OT expansion and bi-direction microactuator are presented in this paper. An expansion arm and a microswitch-like OT microactuator with 1200 mu m-length are fabricated by an excimer laser micromachining system using single layer material. A laser diode (650nm) is employed as the external power source to activate the arm and the microactuator. Experimental results indicate that the OT expansion increment is approximately linear with the laser power irradiating the expansion arm, coinciding with theoretical predictions quite well. As to the switch-like microactuator, an enlarged bi-direction deflection has been obviously observed. The OT expansion and deflection amplitude that can reach micron scale is generally large enough for most microsystems. The new technique of OT microactuators can be widely applied in those fields where simple structure, easy fabrication, large displacement, wireless and remote controlling are required. (C) 2008 Optical Society of America