Superresolution reflection microscopy via absorbance modulation: a theoretical study.

Absorbance modulation enables lateral superresolution in optical lithography and transmission microscopy by generating a dynamic aperture within a photochromic absorbance-modulation layer (AML) coated on a substrate or a specimen. The applicability of this concept to reflection microscopy has not been addressed so far, although reflection imaging exhibits the important ability to image a wide range of samples, transparent or opaque, dielectric or metallic. In this paper, a simulation model for absorbance-modulation imaging (AMI) in confocal reflection microscopy is presented and it is shown that imaging well beyond the diffraction limit is feasible. In addition, we derive analytical design equations and estimate the dependence of the achievable resolution and pixel dwell time on relevant parameters, such as the AML properties and the applied light powers. We prove the validity of these equations through a comparison with the simulation results and we show that a resolution enhancement down to 1/5 of the diffraction limit is possible.