Infrared and Raman spectroscopy of the organic crystal DAST: Polarization dependence and contribution of molecular vibrations to the linear electro-optic effect

Solid State Physics, ETH Zu ¨rich, CH-8093 Zurich, Switzerland~Received 31 May 2001; revised manuscript received 27 December 2001; published 26 November 2002!We use infrared spectroscopy and Raman scattering to show that molecular vibrations considerably contrib-ute to the linear electro-optic effect in the highly nonlinear optical organic crystal 4-N,N-dimethylamino-4