Kdp Crystal Laser Damage Threshold And Theoretical Simulation

KDP/DKDP crystals are non-linear optical crystal materials with excellent optical properties. The investigation of crystal growth has been lasting for more than 70 years. The type of crystals has been one of the lasting water-soluble crystals and has been widely applied in the high technology fields such as laser frequency conversion, electro-optic modulation and optical rapid switch etc.In recent years, with the development of Inertial Confinement Fusion (ICF), the investigation of large KDP/DKDP crystals with high laser damage threshold and their optical properties has entered a new phase internationally. Although many new non-linear materials have been turning up constantly, considering the excellent optical properties and the requirement of large crystal, so far KDP/DKDP crystals are the only kind of crystals that meet the requirement of high-power laser system such as ICF. So the investigation of the growth of large KDP crystals has been paid attention to at home and aboard at present. The requirements of KDP/DKDP crystals in ICF include not only large size, but also their excellent optical qualities such as high laser damage threshold, low optical absorption, high optical homogeneity and wide transparent wave band.In my thesis, the laser damage mechanisms and Sulfate replacement of potassium dihydrogen phosphate (KDP) were studied by the first-principles simulation method and the density of its states was calculated. We found that sulfate can reduce the band gap of KDP crystal to 3.90eV (318nm), which is consistent with the experimental work of others and indicates that sulfate may be a source of the low damage threshold.