Electrically controllable liquid crystal random lasers below the Fréedericksz transition threshold

Chia Rong Lee, Jia De Lin, Bo Yuang Huang, Shih Hung Lin, Ting Shan Mo, Shuan Yu Huang, Chie Tong Kuo, Hui Chen Yeh

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)


This investigation elucidates for the first time electrically controllable random lasers below the threshold voltage in dye-doped liquid crystal (DDLC) cells with and without adding an azo-dye. Experimental results show that the lasing intensities and the energy thresholds of the random lasers can be decreased and increased, respectively, by increasing the applied voltage below the Fréedericksz transition threshold. The below-threshold-electric- controllability of the random lasers is attributable to the effective decrease of the spatial fluctuation of the orientational order and thus of the dielectric tensor of LCs by increasing the electric-field-aligned order of LCs below the threshold, thereby increasing the diffusion constant and decreasing the scattering strength of the fluorescence photons in their recurrent multiple scattering. This can result in the decrease in the lasing intensity of the random lasers and the increase in their energy thresholds. Furthermore, the addition of an azo-dye in DDLC cell can induce the range of the working voltage below the threshold for the control of the random laser to reduce.

Original languageEnglish
Pages (from-to)2391-2400
Number of pages10
JournalOptics Express
Issue number3
Publication statusPublished - 2011 Jan 31

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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