Laser direct-writing is an important technique for the fabrication of complex patterns. There is a continuous need for structures with increasingly small features, i.e., enhanced resolution. Focused radially polarized light is known to exhibit a narrow longitudinal polarization component. Here, a proof-of-concept is shown of enhanced resolution through polarization-selectivity by the selective recording of the longitudinal polarization component in a polarization-selective homeotropic and smectic B photoresist. The full-width-at-half-maximum (FWHM) of the fabricated spots in the polarization-selective resist is up to 56% smaller compared to the FWHM of the same spot in a photoresist that is not polarization-selective, which supports simulations that predict a theoretical maximum reduction of 62%.
A circular wire grid polarizer (WGP) as a device to produce high quality radially polarized light at near UV wavelength range (in particular at the wavelength of λ=405 nm) is presented starting from design modeling followed by fabrication and performance analysis. The wire grid consists of concentric subwavelength metallic cylinders covering a high quality glass substrate and fabricated using an electron beam pattern generator and etching techniques. The theoretical modeling using the rigorous finite-element method and measurements of the transmitted light through the mask have been evaluated. An analysis on adjustments of the geometry of the WGP to produce the optimum focused spot of the longitudinal component of the electric field, its implementation, and qualitative testing are also presented.