Criteria for the research of new materials for opto-mechanical devices

The technology allowing the transformation of light energy into mechanical deformation in a photo-mechanical device is reported. The most efficient materials used for designing such actuators are mainly ceramics made of ferroelectric oxides. They need to be polarised under high DC field in order to activate their piezoelectric properties. The origin of the photo-mechanical effect can be pyrostrictive or ferrostrictive. The most appropriate materials should exhibit both photo-ferroelectric and piezoelectric properties, so that appropriate dopings should increase their light-sensitivity as well as the piezoelectric coefficients. However, a number of parameters plays a part in optimising performances, mainly the composition but also chemical processing, sintering conditions, ceramic texture, orientation of the polarisation. Some improvements are proposed in order to increase the efficiency of such photostrictive actuators.