Laser modification of high-pressure high-temperature nanodiamonds

Micro-thin semitransparent films of purified high pressure high temperature nanodiamonds were produced on a glass substrate. A focused 632.8 nm He-Ne laser irradiation is shown to cause an emission of light in the green region of the optical spectrum accompanied with laser-induced blackening of the obtained films. Possible mechanisms of the observed phenomenon are discussed. (paper)