Demonstration of frequency encoding in neutral atom lithography

We demonstrate a frequency encoding technique for feature placement in atom lithography. Frequency encoding is widely used in MRI, where the frequency distribution of radio waves reveals the position distribution of nuclei in a magnetic gradient. Applied to neutral atom lithography, frequency encoding enables continuously adjustable feature positions and feature densities not limited by the optical wavelength, unlike intensity- or polarization-based patterning. Lines as narrow as 0.9 ± 0.1 μm are fabricated on silicon and gold substrates when exposed to a metastable argon beam through two mask configurations of up to six laser beams.