Rapid Growth of the Gradient Deuterium Deuterated Potassium Dihydrogen Phosphate Crystal

Using broadband lasers is an effective method to suppress laser-plasma instability. In order to achieve efficient broadband third-harmonic generation, a new-type gradient deuterium deuterated potassium dihydrogen phosphate (DKDP) crystal with a gradient refractive index is designed and grown. A gradient deuterium DKDP crystal with a size of 20 x 20 x 80 mm is grown by using the "point-seed" rapid growth method, which has a deuterium content change of 10% along the type-II phase matching direction. The properties of the gradient deuterium DKDP crystal are evaluated by measuring the deuterium gradient distribution, crystalline quality, and transmission spectrum. The gradient deuterium DKDP crystal grown by us provides the possibility for group velocity matching and an efficient conversion process of broadband laser third-harmonic generation.