Laser Imaging of Small-Scale Structural Inhomogeneities in CVD Diamond

The paper reports a possibility of using high-power femtosecond laser pulses for imaging and subsequent study (by means of optical microscopy) of small-scale structural inhomogeneities in synthetic diamond single crystals. The irradiation of diamond by laser pulses in the intense self-focusing mode creates conditions for multiple optical microscopic breakdowns, whose distribution in the diamond bulk reflects spatial oscillations of local breakdown threshold. The breakdown-produced sp² inclusions form ordered stripe microstructures with a characteristic period of several microns. It is shown that spatial oscillations of breakdown threshold correlate with changes in the local concentration of impurity–vacancy defects NV and SiV.