The Research Of The Preparation And Properties Of A Doped-dye Cholesteric Liquid Crystal Laser

The doped-dye cholesteric liquid crystal laser was prepared based on the opticproperty of cholesteric liquid crystal. This type of laser has some advantages, such ascompact structure, all organic, mirrorless, narrow linewidth, low-threshold, and tunable.So the photonic crystal tunable laser based on LCs has wide applications in opticaldisplays, optical communication, photonic integration, biomedical engineering andNon-trace detection etc.. The kind of laser on wavelength tuning condition given,because of the periodicity of the liquid crystal structure is very sensitive to externalenvironments, such as temperature, electric field, magnetic field and mechanical stress.In this paper, first of all, the dye-doped cholesteric liquid crystal laser backgroundand significance of at home and abroad, the basic concepts of liquid crystal and laserand the principle of distributed feedback lasers were introduced, through its concept andcombine knowledge of the cholesteric liquid crystal and the laser characteristics of eachattempt using a dye-doped cholesteric liquid crystals to achieve the distributed feedbacklaser. Secondly, the cholesteric liquid crystal device’s photon density of states and theselective reflection spectra were simulated by the photon group velocity is zero atphotonic band gap and Berreman’s4×4matrix, respectively, base on photon density ofstates and the Bragg selective reflection theory, and then the results were compared andanalyzed with the experimental. Finally preparation of the three different ways of tuninga dye-doped cholesteric liquid crystal laser, and studied it. In accordance with thegeometry of the cell will be divided into parallel and wedge cell. In parallel cell, usingtemperature to tune output laser, and the results were analyzed, in the temperaturetunable laser, output laser wavelength from662nm moved to622nm with temperaturefrom18℃to30℃, the tuning range of40nm. In the wedge cell, among which the useof pitch change in the disclination obtained the wavelength tuning range ofapproximately17nm, and the tuning resolution of1nm; two kind of cholesteric liquidcrystal were mixed and form concentration gradient, in this device, it’s obtainedemission wavelength of laser from558-624nm, the tuning range of66nm and the tuning accuracy of1nm. In the end, compare it with the theoretical analysis of the experimentalresults and theoretical simulations match very well.