All-optically controllable random laser based on a dye-doped polymer-dispersed liquid crystal with nano-sized droplets

作者：Lee C R^*; Lin S H; Guo C H; Chang S H; Mo T S; Chu S C

来源：Optics Express, 2010, 18(3): 2406-2412.

DOI：10.1364/OE.18.002406

This study elucidates for the first time an all-optically controllable random laser in a dye-doped polymer-dispersed liquid crystal (DDPDLC) with nano-sized LC droplets. Experimental results demonstrate that the lasing intensity of the random laser can be controlled to decrease by increasing irradiation time/intensity of one green beam, and increase by increasing the irradiation time of one red beam. The all-optical controllability of the random laser is attributed to the green (red)-beam-induced isothermal nematic -> isotropic (isotropic -> nematic) phase transition in LC droplets by trans -> cis (cis -> trans back) isomerization of azo dyes. This isomerization may decrease (increase) the difference between the refractive indices of the LC droplets and the polymer, thereby increasing (decreasing) the diffusion constant (or transport mean free path), subsequently decreasing the scattering strength and, thus, random lasing intensity.

• 出版日期2010-2-1