Potassium Titanyle Arsenate (KTA) crystals feature large non-linear optical and electro-optical coefficients in comparison to KTP and have the added benefit of significantly reduced absorption in the 2.0 - 5.0 µm region. The large non-linear coefficients are combined with broad angular and temperature bandwidths. Additional advantages of the Arsenates are low dielectric constants, low loss tangent and ionic conductivities orders of magnitude less than KTP. Single crystals of these Arsenates are chemically and thermally stable, non-hygroscopic and are highly resistant to high intensity laser radiation. For second harmonic generation (SHG), sum and difference frequency generation (SFG)/(DFG), optical parametric oscillation (OPO), electro-optical Q-switching and modulation and as substrates for optical waveguides. OPO devices based on these crystals are reliable, solid state sources of tuneable laser radiation exhibiting energy conversion efficiencies above 50%. KTA has a very high damage threshold. No optical damage was observed at levels 10 - 20 GW/cm2 with pico second dye laser. This crystal is grown using high temperature flux technique.