Subwavelength interference with deep ultraviolet superlens

In this work, we propose a deep ultraviolet superlens based on simple metal–insulator–metal (MIM) plasmonic cavity structure under the 193nm wavelength illumination. Through launching surface plasmon polariton (SPP) with high spatial frequency, the subwavelength interference patterns with half-pitch resolution down to 32nm—one-fourth of the grating period and one-sixth of the illumination wavelength—are achieved in a 25nm thick photoresist (Pr) layer. Furthermore, the air working distance could be increased to 40nm. In comparison with superlens operating at 365nm wavelength, this deep ultraviolet superlens could enlarge the Pr thickness and working distance for same half-pitch resolution, which may enhance the interference patterns quality.