Title :
Switchable Random Laser From Dye-Doped Polymer Dispersed Liquid Crystal Waveguides
Author :
Xiao, Shumin ; Song, Qinghai ; Wang, Feng ; Liu, Liying ; Liu, Jianhua ; Xu, Lei
Author_Institution :
Dept. of Opt. Sci. & Eng., Fudan Univ., Shanghai
fDate :
5/1/2007 12:00:00 AM
Abstract :
A dye-doped polymer-dispersed liquid crystal (PDLC) film has been fabricated for random lasing action. In this PDLC film, the sizes of most liquid crystal (LC) droplets ranged from 200 to 500 nm. When the sample is optically pumped, ultrahigh Q (>10 000) lasing modes and a collimated laser beam can be observed. The threshold of the random laser is shown to be 0.23 mJ/cm2. Additionally, a 9.2-V/mum external electric field was applied to control the orientations of LC molecules, thereby obtaining a switchable random laser. Consequently, the linewidth, intensity, and polarization of the emitted random laser are controlled
Keywords :
Q-factor; drops; dye lasers; electro-optical switches; laser beams; laser modes; light polarisation; light scattering; liquid crystal devices; liquid films; liquid lasers; optical pumping; polymer dispersed liquid crystals; spectral line breadth; waveguide lasers; 200 to 500 nm; collimated laser beam; dye-doped polymer dispersed liquid crystal films; emitted laser polarization; external electric field; laser intensity; laser linewidth; liquid crystal droplets; liquid crystal molecules; multiple light scattering; optical pumping; polymer dispersed liquid crystal waveguides; random lasing action; switchable random laser; ultrahigh Q lasing modes; Laser excitation; Laser modes; Liquid crystal polymers; Liquid waveguides; Optical control; Optical films; Optical waveguides; Polymer films; Pump lasers; Waveguide lasers; Optical scattering; polymer-dispersed liquid crystal (PDLC); random laser; waveguide;
Journal_Title :
Quantum Electronics, IEEE Journal of
DOI :
10.1109/JQE.2007.893013
