FRG: A Mechanical Signature of the Polarization of Light: The Opto-Mechanical Effect in Glass

Lehigh University, Bethlehem PA

Investigators

Abstract

Numerous applications of advanced photonics require conversion of an optical signal to mechanical signal. Currently such signal transformation is accomplished only with the intermediate use of appropriate electronics at a significant cost and loss of signal quality. The recent report of the opto-mechanical effect (OME) in a chalcogenide (AsSe) glass film predicts the possibility of faithfully transforming optical information into mechanical signal, bypassing the intervention of electronics. The OME also shows potential use in nano-devices such as nano- actuators, nano-sensors, nano-switches etc. Clearly, the discovery of OME has potential of starting a new area of materials science and make significant impact on technology. However, at present even the defining parameters and the fundamental origin of OME are not known. They are the subject of this Focused Research Group (FRG) proposal. It is built on the initial success of a Small Grant for Exploratory Research (SGER) provided by NSF less than a year ago for experiments at Lehigh, in collaboration with the Cambridge group that discovered the effect. From the project, an atomistic understanding of OME by combining theoretical simulations with the experimental observations of light-induced changes in the electronic and physical structures of glass, and the direct observations of the effect as a function of various parameters will be obtained. Three model chalcogenide glass systems will be studied, with the intent of using the new data for developing superior compositions with stronger effect and faster kinetics. The OME is a vector optical phenomenon (depending on the E vector), which is superimposed on scalar light-induced changes in the structure of glass. Using an improvised setup, the PIs will establish the microscopic origin of the former by polarized x-rays from a synchrotron. Naturally the understanding of scalar effects will be a valuable byproduct, which will help clarify various other light-induced phenomena in similar glasses, such as photo-darkening, photo-expansion, photo-melting, photo-plasticity, photo-crystallization, etc. This project will study a newly discovered phenomenon, the optomechnical effect, in glasses. This new phenomenon has potential to radically improve the quality of telecommunications. In addition, it has potential applications in extremely small devices. The project combines complementary expertise of two experimental groups (H. Jain at Lehigh University and S.R. Elliott at Cambridge University in the United Kingdom) and one theory group (D.A. Drabold at Ohio University) as Principal Investigators. It will also provide to several students and postdocs an unusual opportunity for international, interdisciplinary materials research integrating experiments with theory. The students will periodically meet and exchange places and conduct work under the supervision of the three PIs. This Focussed Research Group project is co-funded by the Ceramics Program in the Division of Materials Research and the Office of Multidisciplinary Activities in the Directorate for Mathematical and Physical Sciences. ***