An experimental study of the photo-isomerization dynamics in dye-doped nematic crystals is reported, which shows that, when the sample is illuminated by a Gaussian beam, and for high enough input power, a transition from the nematic to the isotropic phase takes place in the illuminated area. The two phases are spatially connected via a front propagating outward from the center of the beam and following the local intensity profile and thus inducing a photo-controlled optical aperture. The optical intensity and temperature fields on the sample follow the same dynamical profile. The front dynamics is described by a phenomenological bi-stable model with an inhomogeneous control parameter, directly related to the beam intensity profile.
© 2014 Optical Society of America
Original Manuscript: November 18, 2013
Revised Manuscript: January 27, 2014
Manuscript Accepted: February 14, 2014
Published: March 21, 2014
V. Odent, M. G. Clerc, C. Falcón, U. Bortolozzo, E. Louvergneaux, and S. Residori, "Photo-isomerization fronts in dye-doped nematic liquid crystals," Opt. Lett. 39, 1861-1864 (2014)