All-optically controllable random laser based on a dye-doped liquid crystal added with a photoisomerizable dye

Chia Rong Lee, Jia De Lin, Bo Yuang Huang, Ting Shan Mo, Shuan Yu Huang

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)

Abstract

This study investigates, for the first time, an all-optically controllable random laser based on a dye-doped liquid crystal (DDLC) cell added with a photoisomerizable dye. Experimental results indicate that the lasing intensity of this random laser can be all-optically controlled to decrease and increase sequentially with a two-step exposure of one UV and then one green beam. All-optically reversible controllability of the random lasing emission is attributed to the isothermal nematic(N)→isotropic(I) and I→N phase transitions for LCs due to the UV-beam-induced trans→cis and green-beam-induced cis→trans back isomerizations of the photoisomerizable dye, respectively. The former and the latter can decrease and increase the spatial fluctuations of the order and thus of the dielectric tensor of LCs, respectively, subsequently increasing and decreasing the diffusion constant (or transport mean free path), respectively, and thus decaying and rising the scattering strength for the fluorescence photons in their recurrent multi-scattering process, respectively. The consequent decrease and increase of the lasing intensity for the random laser and thus the rise and descent of its energy threshold are generated, respectively.

Original languageEnglish
Pages (from-to)25896-25905
Number of pages10
JournalOptics Express
Volume18
Issue number25
DOIs
Publication statusPublished - 2010 Dec 6

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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