The Effect Of Sc³⁺ And [Li]/[Nb] Ratio On The Holographic Storage In Sc:Ru:Fe:LiNbO₃

The Sc:Ru:Fe:LiNbO₃ crystals with different Sc doping concentrations（0,1,2and 3 mol%）and different[Li]/[Nb]ratios（0.94,1.05,1.20 and 1.38）were grown by the Czochralski method.The optimal growth conditions were determined,and problems such as cracking during crystal growth were solved.Then,the growth crystal were be polarization,cutting,grinding and polishing.The defect structure and ion occupancy of the crystal were tested by X-ray diffraction and IR spectra.It was found that changing the Sc doping concentration and change the[Li]/[Nb]ratio did not produce a new phase,the dopant ions come into lattice by replaced the Nb or Li sites instead of entering the lattice gap.But because of the radius and polarization is different so the lattice changes.The infrared absorption peak slightly moves in a certain range when the variable change is small,but when the Sc doping concentration reaches 3 mol%,and when[Li]/[Nb]increas to 1.38,the absorption peak shifts to the short-wave direction obviously.The photorefractive properties of Sc:Ru:Fe:LiNbO₃ crystals were tested by traditional two-wave coupling experiments.It is found that with the increase of the concentration of Sc doping and the increase of the[Li]/[Nb]ratio,the response time of the crystal is shortened,the dynamic range is increased,and the photorefractive sensitivity is enhanced.The doping ions Sc and[Li]/[Nb]ratio affect the photorefractive properties by affecting the occupancy and defect concentration of ions instead of directly involved in the transport process of photo-excited carriers.Finally,light-induced scattering of Sc:Ru:Fe:LiNbO₃ crystal was characterized quantitatively via the incident exposure energy method.There is a significant enhancement after the Sc doping reaches threshold concentration.The exposure energy of the sample ScRuFe-3 is 280.77 J/cm²,compared with the ScRuFe-0exposure energy is 280.77 J/cm²,which is increased by two orders of magnitude.The[Li]/[Nb]ratio also increases the resistance of the crystal to light damage.At the same time,there is a certain synergy between Sc and[Li]/[Nb].The exposure energy of ScRuFe_1.38 is 760.50 J/cm² which is 2.7 times higher than that of the sample ScRuFe-3.The Sc:Ru:Fe:LiNbO₃ crystal is a promising material can be applied in holographic storage.