Nano Slit And Dot Array Pattern Of Au On SiO2 substrates Using Laser Beam Lithography

Abstract

Highly monochromatic coherent light intensity of lasers provides the possibility of fabricating periodic nano-patterns which are needed in many applications. Here, we report 2D grating structure and periodic nano hole and dot arrays fabricated using two laser beam interference lithography. Using this method periodic grating as well as dot patterns have been fabricated with structure size of 50 -100 nm and pitch of 200-300 nm on SiO2 substrate. The nano-patterns are formed by inverting an array of photoresist posts by a lift-off process and subsequent reactive-ion etching using chromium as an etch mask. The depth of patterns can be tuned simple by laser dose to obtain high aspect ratio gratings. Transmission spectra measured in Au slits shows strong resonance features at 520 and 640 nm. Finite difference time domain simulations are used to estimate the near-field enhancement at the center of the slit pattern.