ABSTRACT

This chapter explores the fundamental operating principles and unique attributes of a wide variety of light-activated nano- and microactuators. It begins with a brief look at how light can exert pressure on mechanical structures and even levitate artificial micro-objects. The chapter introduces light-driven nanomotors comprised of single protein or DNA molecules that are able to switch between states causing the mechanism to shrink and expand like an inchworm. It examines several direct methods of optical actuation that take advantage of newly engineered photoresponsive materials. The chapter describes indirect optical actuation methods, caused by the photothermal interactions arising from light striking a material surface. The principles of light material interactions are discussed and applications involving diaphragm actuators and light-driven microflows are introduced. In addition, examples of temperature-induced phase transformation of solids and photothermal vibrations of optical waveguides for mechanical actuation are presented. Heat capacity is a measureable physical quantity related to heat, mass, and change in temperature.