Growth And Characterization Of Amino Acid Doped KDP Crystals

KDP?KH₂PO₄?crystals are widely used in electro-optical modulation,Q-switching and piezoelectric transducers due to their high optical transmittance,piezoelectricity,electro-optic,ferroelectricity and high laser damage threshold.Inertial confinement fusion?ICF?research has received much attention in various countries,and KDP crystals are the only nonlinear optical?NLO?materials available for high power lasers in ICF systems.Most amino acids have nonlinear optical properties,so researchers have conducted intensive research on amino acid-doped KDP crystals in recent years.In this paper,L-phenylalanine and L-serine were used as matrixes to study the stability,crystal growth,thermal stability and optical properties of doped KDP solution.The main contents are as follows:1. The solubility and metastable zone width of different concentrations of L-phenylalanine and L-serine-doped KDP solution were determined by weighing method and cooling method.The reason for the decrease in the metastable zone width of the L-phenylalanine-doped KDP solution was explained by the solution-induced nucleation theory.2. High-quality seed crystals were prepared by solution evaporation method.L-phenylalanine and L-serine-doped KDP crystals were grown by the combination of solution cooling and rotating seed crystals.3. The doping mechanism of L-phenylalanine-doped KDP crystals was investigated.X-ray diffraction?XRD?and Fourier transform infrared spectroscopy?FT-IR?and X-ray photoelectron spectroscopy?XPS?test analysis concluded that L-phenylalanine was incorporated into the crystal in a wrapped form.Ultraviolet-visible spectroscopy?UV-Vis?testing showed that the doped KDP crystals had higher transmittance throughout the visible region than pure KDP crystals.The transparency of the KDP crystal is maximized when doped with 1 mol%.The TG/DTA thermal analysis data showed that the doping of L-phenylalanine did not reduce the thermal stability of the KDP crystal.The laser damage threshold test shows that the crystal damage threshold after doping reaches a higher value?1.35GW/cm²?.As the doping concentration increases,the laser damage threshold of the crystal decreases.4. The optical transmittance and thermal stability of L-serine-doped KDP crystals were investigated.XRD and FT-IR tests proved that L-serine doping entered KDP crystal.UV-Vis test showed that L-serine doping increased the optical transmittance of KDP crystal,especially in the ultraviolet region,the transmittance was obvious.Improvement.As the concentration of L-serine increases,the transmittance of the crystal becomes larger and tends to be constant,and the transmittance reaches about90%.The thermal decomposition process of L-serine-doped KDP crystals was analyzed.It was found that the doping of L-serine changed the decomposition point of KDP crystals.The reason may be that the change in thermal stability occurs due to lattice distortion caused by L-serine entering KDP.