| Deuterated potassium dihydrogen phosphate[K(Dx H1-x)2PO4,DKDP]crystal is an excellent nonlinear optical crystal material.Compared with potassium dihydrogen phosphate?KH2PO4,KDP?crystal,DKDP crystal has a higher nonlinear coefficient and transmittance,which is also used as nonlinear optical materials to achieve fourth harmonic generation?FHG?.In addition,deuterated potassium dihydrogen phosphate crystal can reduce the effect caused by the stimulated Raman scattering,and change its refractive index to achieve lower non-critical phase matching temperature.Optical quality is the main factor that restricts its nonlinear performance and FHG conversion efficiency.In this paper,KDP/DKDP crystal with different growth parameters was grown by the point-seed rapid growth method.The deuterium segregation and the transmission uniformity of a series of DKDP crystals with different deuteration degree and growth temperature were tested and analyzed.It is found that the control of supersaturation is particularly critical for crystal growth.The accuracy of the crystal growth was confirmed by powder XRD.The change of lattice constant of DKDP was calculated.The deuterium content in crystal was determined by Raman spectroscopy,and the difference of DKDP deuterium uniformity and transmittance in different growth temperature ranges was analyzed.The homogeneity of individual crystals was compared with different sampling positions of different DKDP crystals.It is found that the lower supersaturation can make the spatial segregation of deuterium content smaller in the rapid growth process when the supersaturation is properly controlled to ensure the transverse expansion of the crystal.The near infrared transmittance and the cut-off range of crystal cone decrease slightly,but the UV transmittance is much better than that of cylindrical edge sampling.At the same time,the transmittance of the space symmetry position and the transmittance of the same sample locations with different thickness were compared. |
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