Photomechanical materials and applications: a tutorial

The transistor has revolutionized civilization. The photon will enable the next revolution provided that photomechanical materials, which convert light energy into mechanical work, can be made substantially more efficient. This tutorial develops a unified picture of the photomechanical response from its microscopic origins to the bulk response. A statistical model of the relationship between the photomorphon, the smallest photomechanical material unit, and the bulk response provides the context for understanding the various mechanisms that can contribute. We then present experimental details of how the photomechanical response is measured and used to deduce the underlying mechanisms. A figure of merit for the photomechanical efficiency is defined and materials are reviewed. Finally, we describe the photomechanical optical device (POD) and how PODs can be combined to form highly intelligent materials. This tutorial spans the multidisciplinary topics needed to (1) understand the fundamental physics of the response, (2) design and process materials to control the response, and (3) build new devices and integrated photomechanical systems.