Photostriction in CaTiO3 ceramics under the illumination of a light emitting diode

Abstract

Ceramics, sensitive to feeble illumination, to show a significant photostrictive effect, are of great interest for micro-opto-mechanical applications. Despite applying a high laser power, relatively a small photostriction has been reported so far, in both simple and complex composition based ceramic systems. Here, we report CaTiO₃ ceramics for a high photostrictive efficiency of 0.2 × 10⁻¹⁰ m³ W⁻¹ corresponding to the photostriction ΔL/L = 0.15‰ under the illumination of a 365-nm light emitting diode at an intensity of 2 sun. Of particular significance, a sharp rise/decay of 6–8 s and hysteresis-less photostriction is obtained while having a very low influence from thermal effect of light. In the investigation of the underlying mechanism, the light triggered tensile strain, generated on account of polyhedral distortions and the stretching of bond lengths, is found to be related with light-induced mechanical vibrations of optical-phonon and optical-acoustic phonon scatterings. The efficient photostriction characteristics identified in this study make CaTiO₃ ceramics a potential candidate for advanced micro-opto mechanical devices, like micro-motors, micro-relays, micro-switches, and so on, all to be controlled by the wavelength and intensity of light.