Growth And Properties Of Yb³⁺ Doped Rare Earth Polyvanadate And Orthophosphate Laser Crystals

As an important part of solid-state laser,laser crystals have always been a research hotspot in the field of scientific research.Vanadate and phosphate crystals have been widely used as laser dielectric materials because of their excellent physical and chemical properties.The trivalent rare earth ions(Yb³⁺)are also used in the field of laser crystals due to their broad band absorption and emission and unique energy level structure.The laser diode(LD)pump source matching with the absorption spectrum of Yb³⁺also promotes the application of Yb³⁺in the field of laser crystals.In this paper,the Czochralski method was used to grow the thin films with the size of?19×25 mm³ Yb:Ca₉Gd(VO₄)₇ crystal.The synthesis of polycrystalline materials,crystal growth,phase analysis,polarization absorption and fluorescence spectra,energy level distribution,fluorescence lifetime and laser performance parameters were studied in detail.The full width at half maximum(FWHM)of the peaks are 33 nm(?)and 28 nm(?);The FWHM of the emission peaks are 57 nm(?)and 54 nm(?).The results show that Yb:Ca₉Gd(VO₄)₇ is a potential ultrafast pulsed laser crystal material.In this paper,the crystal of Nd,Yb:YPO₄ with the size of 3×7×0.5 mm³ were grown by high temperature solution method with lead pyrophosphate(Pb₂P₂O₇)as flux.Crystal growth,polarization absorption and fluorescence spectra,energy level transition,fluorescence lifetime and laser performance parameters were studied.The emission peaks of Yb³⁺and Nd³⁺ions at 1002 nm and 1060 nm were observed in the fluorescence spectra of the crystal.The calculated results show that the Yb³⁺and Nd³⁺ions can produce radiation in the range of 17-21 THz.The results show that Nd,Yb:YPO₄ is a promising dual wavelength laser crystal,especially the orthogonal polarized dual wavelength laser,which can be used as the source of terahertz radiation.Using Pb₂P₂O₇ as flux,the Yb:Lu YPO₄ crystal with size of 5×3×0.4 mm³ were successfully grown.The crystal structure,polarization absorption,fluorescence spectrum,fluorescence lifetime and laser properties were studied.When the output coupling transmittance T=2%,the optimal laser output of Yb:Lu YPO₄ crystal is realized.The corresponding laser output power is 0.81 W,slope efficiency is 12.1%,and the optical-optical conversion efficiency is 10.3%.The results show that Yb:Lu YPO₄ is a potential laser crystal material.