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

C. R. Lee, S. H. Lin, C. H. Guo, S. H. Chang, T. S. Mo, S. C. Chu

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

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)-beaminduced 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.

Original languageEnglish
Pages (from-to)2406-2412
Number of pages7
JournalOptics Express
Volume18
Issue number3
DOIs
Publication statusPublished - 2010 Feb 1

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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