CVD SINGLE CRYSTAL DIAMOND MATERIAL

摘要

A single crystal diamond material, when measured at room temperature comprises; a longest linear internal dimension greater than 7 mm, a birefringence of below 1x105determined using a light beam with a cross sectional area greater than 0.01 mm2and along an internal path greater than 7 mm, and an absorption coefficient below 0.010 cm-1determined at a wavelength of 1064 nm. The diamond material may have a concentration of single-substitutional nitrogen in a neutral charge sate of equal to, or less than, 1x1015atoms/cm3. A method of producing the single crystal diamond material comprises chemical vapour deposition (CVD) with multiple growth stages, at least two of the growth stages having different nitrogen concentrations, one of which has a molecular nitrogen concentration of 300 ppb - 5 ppm and the other a molecular nitrogen concentration of 0.001 ppb — 250 ppb. The use of the single crystal diamond material in a Raman laser is also disclosed.