Pump-Controlled Plasmonic Random Lasers from Dye-Doped Nematic Liquid Crystals with TiN Nanoparticles in Non-Oriented Cells

Abstract

Manipulation of the performance of the random lasers from dye-doped nematic liquid crystals with TiN nanoparticles in non-oriented cells is studied. The experimental results show that the introduction of TiN nanoparticles into dye-doped nematic liquid crystals significantly reduces the threshold of random lasing due to the localized surface plasmon resonance of TiN nanoparticles. The emission spectrum of random lasers can be controlled by the shape of the pump spot. The threshold of random lasers increases with the decrease of the length of pump stripe. In order to obtain the emission spectrum with fine discrete sharp peaks, the narrow pump stripe is more effective than the circular pump spot. When the pump area is more like a circle, the emission spectrum is more like an amplified spontaneous emission. The underlying mechanisms of these phenomena are discussed in detail. This study provides a promising platform for designing the high-quality and low-threshold random lasers which can be controlled by the shape of the pump spot.

Recent progress and prospects of random lasers using advanced materials

“…Therefore several other scatterers include particles composed of zinc oxide, silica, TiO 2 -silica core-shell, alumina, tungsten oxide and nanoclays, ferromagnetic particles, polymeric fiber networks an even liquid crystals in ordered phases have been used to efficiently scatter light in colloidal RLs. Laser dyes, the most commonly used gain media are incorporated with nanomaterials scatterers such as ZnO, TiO 2 , WO 3 , biological tissues 48 , nematic liquid crystals 49,50,51,52,53,54,55 etc. When the dyes are injected into biologically active tissues, RL is generated in the system, which can be applied to separate cancerous and normal tissues 56,48 .…”

“…Laser dyes, the most commonly used gain media, are incorporated with nanomaterials scatterers such as ZnO, TiO 2 , WO 3 , biological tissues, 48 nematic liquid crystals [49][50][51][52][53][54][55] etc. When the dyes are injected into biologically active tissues, RL is generated in the system, which can be applied to separate cancerous and normal tissues.…”

Review of Random Fiber Lasers for Optical Fiber Sensors

“…By replacing the reflector of a ruby laser with a scattering surface and increasing the pump power, the emission spectrum gradually narrowed. Due to their special structure, RLs have attracted widespread attention and have been used in materials, such as semiconductor powders [2][3][4], liquid crystals [5][6][7], polymers [8][9][10][11], and biological tissues [12,13], to achieve laser emission. However, the above RLs are mostly two-dimensional or threedimensional structures, and the directionality is poor.…”