Fabrication of integrated micro-optical elements via focused laser beams and holographic lithography

Fabrication of planar integrated micro-optical element with sub-wavelength features requires advanced lithography techniques, e.g. UV contact, electron beam, nano-imprint lithography, etc. These systems are expensive or processes are time consuming. As an alternative laser source based photoresist exposure or direct laser ablation methods are frequently applied. In the current work using one long coherence length solid state continuous wave UV laser light source distributed between two optical setups, i.e. Lloyd’s mirror interferometer and Direct Laser Writing (DLW) systems, we were able to pattern micrometer range features together with 100 nm sized lines in photoresist film on silicon and glass substrates. Employing motorized Lloyd’s mirror holographic lithography system and controlling the angle between interfering beams one can fabricate gratings with pitch ranging from 200 to 500 nm. DLW system is based on sample exposure with focused laser beam. The size of the focused spot on the sample surface is less than 5 µm in diameter. The serial exposure of the sample is realized translating it on motorized XY stage. System is capable of patterning integrated photonics applications.