Yb:Sr₃La₂(BO₃)₄ Crystal Growth And Thermal, Spectroscopy, Laser Properties The Study

Disordered laser crystals are a new type of laser media,they possess to some extent the advantages of both laser glasses and laser crystals,and can have important applications in tunable lasers as well as in ultra-short mode-locked lasers.Among the Yb-doped disordered double-borate crystals that have attracted much attention in recent years,Yb:Sr₃La₂?BO₃?₄?Yb:SLB?is one of the few which have not been studied sufficiently.In this thesis work we carried out a comprehensive,deep,investigation into the growth,thermal properties,spectroscopic properties,and continuous-wave laser characteristics of the Yb:SLB crystal.The primary work is summarized as follows:Yb:SLB crystals of high optical quality were grown by employing Czochralski method,the crystal structure and compositions were analyzed.The primary thermal properties of the crystal were measured,including thermal expansion coefficients,specific heat,and thermal diffusion coefficients.The thermal conductivities were calculated.The anisotropy in thermal properties and its effects on laser applications were also analyzed.Polarized absorption and fluorescence spectra were measured,from which the polarized emission spectra were calculated.Under longitudinally diode pumping conditions,high-power continues-wave laser operation was achieved by using a simple plano-concave resonator,with Yb:SLB crystals of different orientations,producing output powers in the range of 7.8 8.2 W,with optical-to-optical efficiencies of 30%32%.Experimental studies indicate that the laser action exhibited different oscillation behavior for crystals of different orientations,showing some anisotropy in laser properties.Depending on the operational conditions,the resulting laser action could have simultaneously two orthogonal polarization states.The c-cut crystal is more suitable for generating high-power single-polarization laser operation;whereas the b-cut crystal could be used in those practical lasers that can oscillate in two orthogonal polarizations over a wide operational range.