Nano and microscale surface and sub-surface modifications induced in optical materials by femtosecond laser machining

Femtosecond laser and optoelectronic materials interaction is studied in this research. Particular focus is on diamond, lithium niobate, and gallium arsenide. The following unique, laser-assisted nano and micromachining findings were observed: (1) 3D periodic nano-writing on the surface and on diamond clusters in the form of periodic ripples shorter than the laser wavelength, (2) amorphous and defective areas in the nano/sub-micrometer vicinity of laser treated region, allowing selective light trapping, and (3) surface passivation without contaminating the surface. These findings demonstrate the suitability of ultrashort lasers to nano/micromachining of difficult-to-machine optoelectronic materials, and this manuscript discusses mechanisms responsible for these.