High-damage-threshold antireflection coatings on diamond for CW and pulsed CO₂lasers

Abstract

A multilayer antireflection coating for diamond optics that allows work in the infrared spectral range of 8 –12 µm with minimal optical losses is developed. The optical transmittance of a chemical vapour deposition diamond plate coated with this film on both sides exceeds 94% over the whole specified wavelength range. The coatings deposited on the diamond plate were damage-tested by coherent-wave and pulsed (τ = 90 ns) CO2 lasers. Results of the tests demonstrated that the coating can withstand prolonged radiation loads with intensity above 3 MW cm−2 in a continuous-mode laser exposure. In the case of a nanosecond pulsed action, destruction of the coating begins at intensities greater than 50 MW cm−2.

Laser power effects on properties of laser brazing diamond coating

“…The limitations of high-frequency induction brazing are mainly the complicated design and manufacture of the coil and the heating range is affected by the shape of the coil [8,9]. Since the laser beam energy with its inherently higher efficiency makes the extent of thermal damage of the diamond grits, and the thermal deformation of the substrate during the laser brazing process better controlled, this method of selecting laser beam for brazing can not only solve the deficiencies in the above two processes, but also obtain a machining tool with good grinding performance [10,11].…”