We present the results of a study of the critical opalescence that is observed as a result of reversible <i>trans–cis</i> photoisomerization in the vicinity of photoinduced isothermal phase transitions in azobenzene liquid crystals (azo LCs). The opalescence is caused by the generation of randomly oriented microdomains and microdroplets of isotropic phase in the illuminated area of the azo LC. Transformations between the strongly light-scattering nematic phase and the transparent isotropic phase of the azo LC are induced all-optically by combination of green (λ=532nm) and violet (λ=409nm) laser beams.
© 2003 Optical Society of America
(160.3710) Materials : Liquid crystals
(190.0190) Nonlinear optics : Nonlinear optics
(210.4770) Optical data storage : Optical recording
(260.5130) Physical optics : Photochemistry
(290.0290) Scattering : Scattering
Nelson V. Tabiryan, Svetlana V. Serak, and Vladimir A. Grozhik, "Photoinduced critical opalescence and reversible all-optical switching in photosensitive liquid crystals," J. Opt. Soc. Am. B 20, 538-544 (2003)