| Nonlinear optical(NLO)crystal is the key material for harmonic generation in all-solid-state lasers.CsLiB6O10(CLBO)crystal is a nonlinear optical crystal with excellent overall performance,but the highly hygroscopic nature of this crystal severely limits its practical application,and Al doping of it can enhance the hygroscopic nature resistance of the crystal.At present,Al-doped CLBO crystals are mainly grown by self-flux system,which have problems such as poor repeatability and low optical homogeneity.?-BaB2O4(BBO)crystals have been widely used in laser frequency doubling,mixing,optical parametric oscillator,and etc.However,the stable growth of large size and high quality single crystals is more difficult,which has become a bottleneck limiting the further application of BBO crystals.In summary,this thesis focuses on the growth and performance characterization of nonlinear optical crystals CLBO and BBO crystals,and the main work and conclusions are as follows:The properties of the crystallization region and saturation point temperature of the flux system were systematically investigated to explore a suitable flux ratio for the growth of CLBO crystals,and a series of transparent crystals with different starting Al doping concentrations(0%,5%,10%)were stably grown,and the maximum size and weight of the crystals were the maximum size and weight of the crystals were60×47×40 mm3 and 107.72 g,respectively.Metal fluorides were introduced into the Cs2O-Li2O-MoO3 system,and the composite flux system Cs2O-Li2O-MoO3-MFx(x=1,M=Na,K;x=2,M=Mg,Ca,Zn,Ba,etc.)were tested for their properties such as crystallization region and saturation point temperature,and undoped CLBO crystal growth studies were carried out,and the maximum size and mass weight of the crystals were 74×51×41 mm3 and 141.19 g,respectively.The properties of the undoped and 5%Al-doped CLBO crystals were characterized.The transmission spectra showed that the transmittance of both crystals is higher than 90%from 230 to 2000 nm.The infrared spectra indicated the presence of water molecules in both crystals.Optical weak absorption showed that both crystals had weak absorption values below 10 ppm/cm in the a and c directions,which were significantly lower than those of conventional undoped CLBO crystals(600ppm/cm and 150 ppm/cm).The optical homogeneity of both crystals was 1.2×10-5/cm and 1.1×10-5/cm,respectively,with high optical quality.The thermal property tests showed that the linear thermal expansion coefficients of the two crystals in the a and c directions were?a=1.81×10-5/°C and?c=-2.98×10-5/°C;?a=1.10×10-5/°C and?c=-2.56×10-5/°C,respectively,with positive expansion in a direction and negative expansion in the c direction,and this difference was related to the spatial structure of the six-membered ring constituted by B3O7 in the crystal.The thermal diffusion coefficients of both crystals in the a and c directions decreased with the increase of temperature.The specific heat and thermal conductivity in the c-direction were 0.935Jg-1K-1,2.66 Wm-1K-1 and 0.916 Jg-1K-1,1.857 Wm-1K-1,respectively.the laser damage thresholds of the two crystals were 7.04 GW/cm2 and 6.69 GW/cm2respectively.The single crystal wobble curves showed that the two crystals had smaller values of half-peak width in the c direction,30.32 arcsec and 28.08 arcsec,respectively,with higher crystalline quality inside the crystal.The flux system for BBO crystal growth was explored,using a new flux system Na F-Li F for BBO crystal growth,the initial determination of the appropriate flux ratio,the growth of BBO crystal size?49×8 mm3 transparent internal BBO crystal. |
PDF Full Text Request