Studies On Metal/Oxide Nano-particles Enhanced Micro-cavity Dye Random Laser Mediu

As a novel microcavity laser medium, the random laser medium has its unique optical feedback mechanism, which has the characteristics of flexible shape design, micro-scale preparation, simple processing and low cost, thus becoming a promising part to be integrated in photonic integration, micro dimensional optics and biosensors. However, applying random laser medium is still being hindered in several aspects. Firstly, the threshold of random laser medium is a bit higher, the photon is scattered out of the gain area because of the light scattering in the gain medium, which increases the loss of the laser; Secondly, due to the lack of the optical resonator, it is not only difficult to tune the output of lasers, but also the stability of the emission spectrum is poor; Therefore, it is necessary to develop a new design to fabricate or prepare scatter and nanostructure to obtain a random laser medium with low threshold, tunable and stable emission.In this paper, we mainly study based on the oxide/metal nanoparticle-enhanced random laser medium, the influences of cattering system and metal nano-structures on the lasing threshold, wavelength tuning and stability of emission spectral have been studied.The disordered flexible waveguide random laser medium was fabricated using a novel nanoplate CuO as a scatterer, which have different luminescence properties in various emission directions, at the same time, equiping with stable coherent emission spectrum. And the tuning width of 8.7nm and 4.13nm were obtained by changing the doping concentration of the sheet CuO nanoparticles as well as the dielectric layer thickness.The localized surface plasmon resonance (LSPR) of metal nanoparticles as scattering centers will induces selective enhancement of the photoluminescence, which is expected to decrease the thresold of random laser (RL) in random system. The silver nanowires and cubic silver nanoparticles were used as the scattering bodies, the overlap of the LSPR of the metal nanoparticles and photoluminescence spectrum has been found to be a factor in fluenceing the threshold of the RL, and the threshold of the cubic silver nanoparticles system is as low as 0.0881 mJ/cm2, and the quality factor Q is 874 because of the sharp edges and corners resulting in more obvious Spot Hot effect; The 439～724 nm continuous coherent random laser output is obtained by using four kinds of laser dyes in the silver nanowires random system.By adjusting the size of the silver nanowires, the tuning of the emission wavelength and the reduction of the laser threshold are realized in the waveguide random laser medium; And the threshold of the random system is significantly reduced due to introduce Au nanogap into the smooth silver nanowires; Then we substantially reduce the threshold and obtain the high Q (1556) random laser output by incorporating an one-side-reflection structure into the RL system.