Micro-cylindrical and micro-ring lenses in CVD diamond

Micro-cylindrical and micro-ring lenses have been fabricated on chemical vapour deposition (CVD) diamond using photo-resist reflow and inductively coupled plasma dry etching. The surface morphology of these micro-lenses was characterized using atomic force microscopy, revealing that they have a root-mean-squared surface roughness of less than 3 nm and a cross-sectional profile close to spherical in shape. The optical properties of the micro-lenses were characterized by a laser scanning transmission/reflection confocal microscope. The measured optical parameters are very close to the calculated values, indicating high structural and surface quality of the micro-lenses. The characteristics of these micro-lenses suggest that the approach used is suitable for fabricating complex diamond micro-optics with various functionalities.