First, the results of available laser-induced damage threshold (LIDT) measurements performed on type IIa single crystals of natural or synthetic origin are reveiwed in the light of an incident irradiance versus laser wavelength plot. It is shown that the multiplicity of the across-the-gap photon absorption essentially determines the nature of the damage process, but true bulk dielectric breakdowns appear to be difficult to achieve because diamond targets are 'optically thin' in most test configurations. The same observation holds for chemically vapor-deposited (CVD) diamond, especially since massive deposits of good optical quality have only recently become available. Upon using the Bettis-House-Guenther (BHG) scaling law for obtaining normalized LIDT values, it is seen that damage thresholds recorded for CVD diamond over a wide range of spot sizes and pulse durations correlate remarkably well with single-crystal surface breakdown data. For picosecond pulses impinging on single-crystal natural or polycrystalline CVD diamonds it is shown that the fieldstrength at the damage threshold (EDB) exhibits a spot size (2(omega) ) dependence best described as follows: EDB equals A(root)2(omega) with A approximately equals 24 MV(root)micrometers /cm in the visible and A approximately equals 48 MV(root)micrometers /cm in the infrared. This demostrates that the optical strength of diamond is comparable to the strength of well established wide-bandgap laser-windows material candidates.
Claude A. Klein, Claude A. Klein,
"Laser-induced damage to diamond: dielectric breakdown and BHG scaling", Proc. SPIE 2428, Laser-Induced Damage in Optical Materials: 1994, (14 July 1995); doi: 10.1117/12.213749; https://doi.org/10.1117/12.213749