UV laser writing system based on polar scanning strategy to produce subwavelength metal gratings for surface plasmon resonance

摘要

We demonstrated the use of ultraviolet (UV) laser lithography in the production of subwavelength structures. A laser writing system with a 413-nm Kr laser was used to write patterns on a resist-coated fused silica substrate mounted on a rotating table with a linear slider. One- and two-dimensional patterns were written on the resist at a fixed sampling frequency, and then, the substrate was dry etched and coated with Au to obtain metallized gratings. Surface plasmon resonance dips, which appeared in the reflectance spectra of the gratings, shifted for different orientations of the incident linear polarization. However, this dip shift can be considered tolerable for practical purposes, provided that the gratings that couple light with surface plasmons are used as a near-field enhancer. Hence, we concluded that UV laser writing based on polar coordinates is a candidate method for submicron-scale structuring.