Optical Electrostriction

摘要

It is well known that the forces which light imparts on micro- and nanoparticles arise due to intensity gradients and dielectric mismatch. For laser-irradiated atoms and molecules, optical forces primarily result from close resonance between the optical frequency and an electronic transition. Recently it has emerged that optically induced pair forces also arise, through a modification of Casimir-Polder interactions; preliminary assessments of the mechanism have largely centered on nanoparticle systems. In this paper, we show that a potentially very significant effect can be anticipated in the condensed phase, an optically induced modification of interatomic forces that is capable of generating anisotropic patterns of laser-induced compression and expansion. This phenomenon, termed optical electrostriction, should be measurable and significant when high intensity laser light is transmitted through even an essentially non-absorptive material. However, the full conditions for observation of the effect are such that some competing interactions might also arise. Key parameters that determine the size and character of optical electrostriction are delineated and possible applications are considered, including optical actuators for nanoscale electromechanical systems.