Crystal Growth And Properties Of La₁-X Sm_xGN Optical Crystals

Laser has been widely used in military and civil fields since its birth in 1960.At present,laser technology is developing in the direction of ultra-short and ultra-strong.Chirped pulse amplification(CPA)and optical parametric chirped pulse amplification(OPCPA)are the two most commonly used laser amplification methods.The conversion efficiency of CPA is high,but the gain bandwidth is narrow.On the contrary,OPCPA has large gain bandwidth,but it's conversion efficiency is low.In order to obtain high conversion efficiency and large gain bandwidth at the same time,a new quasi-parametric chirped pulse amplification(QPCPA)is proposed.In the present work,we doped Sm3+ions into La3Ga5.5Nb0.5014(LGN)crystals to absorb the idle wavelength near 1570nm.The solid reaction method was used to synthesize polycrystalline raw materials and the pure Sm:LGN phase was obtained by optimizing sintering process parameters.La1-xSmxGN(x=0.1,0.2)crystals were grown by the vertical Bridgman method and high quality and transparent crystals were obtained with a dimension of 1 inch in diameter.In this paper,crystal structure and crystallinity,thermal properties,optical properties and laser damage properties of Sm doped LGN crystals were investigated.The segregation coefficient of Sm3+in La0.9Sm0.1GN crystal was 0.140.XRPD results show that La1-xSmxGN and LGN crystals have the same structure,and the cell parameters decrease with the increasing Sm3+ion concentration.The Peak Width at Half Height of La0.9Sm0.1GN and La0.8Sm0.2GN crystals were 47.16 "and 38.16" respectively,which indicates that the crystals have similar qualities compared to LGN crystal.The specific heat,thermal diffusion coefficient and thermal conductivity of the crystal show that the crystal has good thermal properties.The crystals have high transmittance in pump and signal wavelengths,and there are many obvious absorption peaks near the idle wavelength.Under the condition of 800nm wavelength and 35fs pulse width,the laser damage thresholds of La0.9Sm0.1GN and La0.8Sm0.2GN crystals were 188.30 TW/cm2 and 54.84 TW/cm2,respectively.