Rapid growth technology and optical properties of a large aperture high-deuterium DKDP crystal

Abstract

In this paper, a concept of establishing a uniform temperature field range and a “double-layer four-stage continuous filtration circulation system (DF-CFCS)” during crystal growth have been proposed. A high-deuterium DKDP crystal with a size of 411 mm × 433 mm × 250 mm and a weight of 51 kg has been successfully grown by a rapid-growth method. The crystal is the largest-aperture high-deuterium DKDP crystal reported so far and its deuteration rate is 99.38%. The characterization results showed that the transmittance of the DKDP crystal was about 93.88% at a wavelength of 1064 nm, the root mean square (RMS) optical uniformity was 1.51 × 10⁻⁸, the data distribution of the extinction ratio was uniform, and the bandwidth was 4.84 eV. Besides, benefiting from the proposed “DF-CFCS”, the laser-induced damage threshold of the crystal was increased to 40 J cm⁻² (@1064 nm, 3 ns), which is of great significance for the development of ultra-intense and ultra-short laser devices with output power ≥10 PW.