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.

Self-Organized 3D Photonic Superstructure: Blue Phase Liquid Crystal

“…This observation has encouraged the development of 3D tunable laser sources for integrated photonic circuit applications [104,111]. Recently, Chen et al observed the potential for dye doped cubic BPs to give off coherent random laser [112]. Much different from the bandedge lasing, interferences and recurrent multiple scattering arising from the grain boundaries in a BP polycrystal provides the optical feedbacks for such laser action.…”

MAXWELL STRESS INDUCED FLOW-DEFORMATION AND OPTICAL NONLINEARITIES IN LIQUID CRYSTALS (Invited Paper)

“…Recent studies have shown that another mesophase, namely, Blue-Phase Liquid Crystals (BPLC) present promising alternatives to NLC for electro-and nonlinear optics [32][33][34][35][36][37][38][39][40][41][42][43][44]. In this unique class of optical materials formed by mixing a chiral compound and nematics, the molecules self-assemble (without cell-surface alignment) into tightly wound defect-spirals that form 3-D body-centered cubic or simple cubic lattices with sub-wavelength lattice constants, cf.…”

MULTIPLE TIME SCALES OPTICAL NONLINEARITIES OF LIQUID CRYSTALS FOR OPTICAL-TERAHERTZ-MICROWAVE APPLICATIONS (Invited Review)

“…There have also been recent studies of another phase of chiral nematic liquid crystals, namely, Blue-Phase Liquid Crystals (BPLC) and their polymer-stabilized forms (PSBPLC) that presented promising polarization-and alignment-free alternatives [5,[92][93][94][95][96][97][98][99] for nonlinear optics as well as electro-optics. In this unique class of optical materials formed by mixing chiral and achiral nematics (with or without polymer stabilization), the molecules self-assemble into tightly wound defect-spirals that form 3-D cubic or BCC lattices with sub-wavelength lattice constants.…”