title: Random lasing in blue phase liquid crystals.
abstract: Random lasing actions have been observed in optically isotropic pure blue-phase and polymer-stabilized blue-phase liquid crystals containing laser dyes. Scattering, interferences and recurrent multiple scatterings arising from disordered platelet texture as well as index mismatch between polymer and mesogen in these materials provide the optical feedbacks for lasing action. In polymer stabilized blue-phase liquid crystals, coherent random lasing could occur in the ordered blue phase with an extended temperature interval as well as in the isotropic liquid state. The dependence of lasing wavelength range, mode characteristics, excitation threshold and other pertinent properties on temperature and detailed make-up of the crystals platelets were obtained. Specifically, lasing wavelengths and mode-stability were found to be determined by platelet size, which can be set by controlling the cooling rate; lasing thresholds and emission spectrum are highly dependent on, and therefore can be tuned by temperature.
authors.affiliation: Department of Photonics, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Chen
authors.forename: Hung-Chang
authors.initials: HC
authors.lastname: Jau
authors.forename: Chun-Ta
authors.initials: CT
authors.lastname: Wang
authors.forename: Chun-Hong
authors.initials: CH
authors.lastname: Lee
authors.forename: I C
authors.initials: IC
authors.lastname: Khoo
authors.forename: Tsung-Hsien
authors.initials: TH
authors.lastname: Lin
mesh_terms: D003116:Color; D003198:Computer Simulation; D007834:Lasers; D050866:Liquid Crystals / Q000737:chemistry* / Q000528:radiation effects*; D008962:Models, Theoretical; D012542:Scattering, Radiation