Theoretical investigation of optical patterning of monolayers with subwavelength resolution

We formulate a model of monolayer patterning via optically-controlled chemical reactions, with the goal of beating the diffraction limit in photolithography. We consider the use of the proven technique of STimulated Emission Depletion (STED) to selectively place a handful of molecules in a reactive excited state. We show that repeated optical excitation has a greater effect on pattern formation than increasing the reaction rate, auguring well for experimental work. We also consider optically-controlled deposition of a soluble species via STED, and show that even for very large concentrations and excited state lifetimes the full width at half maximum of the features formed is robust against the effects of diffusion and saturation.