Optical surface generation of organic nonlinear crystals by single-point diamond turning

Organic nonlinear crystals that are very soft and brittle have been machined into optical surfaces by single-point diamond turning using special machining conditions. The crystallographic orientations of materials to be cut and rake angles of diamond tools strongly affect the cutting mode. The surface roughness depends upon the cutting direction, rake angle and nose radius of the diamond tool, feed rate and lubricant. The surface roughness is not a factor in the depth of cut or cutting speed. The machined surfaces of 23nm p-v in flatness and less than 1nm rms in surface roughness were obtained.