FREE-SURFACE EFFECTS ON THE RESPONSE OF NEMATIC LIQUID-CRYSTAL FILMS TO A LASER-PULSE

Abstract

The dynamic response of 5CB films with a free surface to a laser pulse is investigated. A magnetic field above the Freedericksz transition is applied initially to induce a starting angle on the molecular orientation. A single 1.06 mum laser pulse with e-1 pulse width 0.2 ms is incident normally upon the films. When the laser pulse polarization is perpendicular to the magnetic field, only a thermal effect is involved. While it is parallel to the magnetic field, both molecular orientation and thermal effects are involved. The results from films with a free surface are compared with those from films sandwiched between two glass substrates. The free surface effect, beam size effect, and thermal effect are discussed by comparing with theoretical analysis.