Constitutive Modeling of Photostrictive Materials and Design Optimization of Microcantilevers

This article presents constitutive models for photo-induced strains in photostrictive materials and an optimal design of microcantilevers driven by light illumination. Behaviors of photo-induced strains in semiconductors and polymeric materials are reviewed first, and then new phenomenological constitutive models are developed that depict two distinctive features of photo-induced strain profile: (a) dependence on variation of light intensity which decreases with the depth measured from the illuminated surface due to light attenuation and energy absorption; and (b) anisotropy or dependence on direction of light polarization. On the basis of the constitutive modeling of photo-induced strain in wafers, design optimization of microcantilevers is then investigated for both geometrically linear and non-linear deformations.