DIAMOND AND RELATED MATERIALS The possibility of laser induced variation of optical and electrical properties of conductive nanocrystalline diamond (CNCD) films has been demonstrated. The films were produced by microwave plasma chemical vapor deposition (MPCVD) from CH4:H2:N2 gas mixtures. The films were irradiated in air with 20 ns pulses of an ArF excimer laser (λ =193 nm). It was found that low laser pulse intensity (~ 0.05 J/cm2), well below film surface graphitization (~