DKDP (deuterated potassium dihydrogen phosphate, KH2PO4) is a type of non-linear optical crystal with excellent thermal, mechanical, and electro-optical properties. In comparison to traditional KDP crystals, DKDP has an enhanced transparency in the infrared range and can be used over a wider frequency range. DKDP single crystals are used in a wide range of applications including: laser frequency conversion, optical parametric oscillators, intra-cavity phase and amplitude modulation, pulse compression, and Q-switched lasers. Additionally, DKDP single crystals have been used for nonlinear optical devices such as second harmonic generators (SHGs) and sum frequency generators (SFGs).