Thresholds for dielectric breakdown in laser-irradiated diamond

Abstract

We report on picosecond laser-induced damage experiments that were carried out on a natural type-IIa diamond and a thick specimen of high-quality chemically vapor-deposited (CVD) diamond. In conjunction with earlier measurements performed elsewhere on an ‘‘optically thick’’ single crystal, it is shown that for spot sizes (2ω) ranging from 3 to 60 μm, the breakdown field strength (EBD) at the damage threshold of diamond obeys a pattern best described as follows: EBD≂A/√2ω, where A=30.7 and 38.7 MVμ1/2/cm at 532 and 1064 nm, respectively. The case of CVD diamond demonstrates that if problems arising from localized high absorption at the deposition surface can be avoided, this material should be of much promise for contemplated high-power free-electron laser window applications.