Optical patterning of features with spacing below the far-field diffraction limit using absorbance modulation.

Absorbance modulation is an approach that enables the localization of light to deep sub-wavelength dimensions by the use of photochromic materials. In this article, we demonstrate the application of absorbance modulation on a transparent (quartz) substrate, which enables patterning of isolated lines of width 60 nm for an exposure wavelength of 325 nm. Furthermore, by moving the optical pattern relative to the sample, we demonstrate patterning of closely spaced lines, whose spacing is as small as 119 nm.