Dynamic deep-ultraviolet beam pattern structuring in nonlinear third harmonic generation by spatial wavefront modulation of near-infrared driving laser

Deep-ultraviolet (DUV, λ<280 nm) light sources are garnering significant attention in semiconductor processes, including lithography and metrology, due to their capability to provide high spatial resolution. However, the strong DUV absorption necessitates specialized optics for beam shaping, which has hindered the development of DUV-based precision metrology. In this paper, we demonstrate a novel beam shaping technique for DUV (λ=266 nm) by manipulating the wavefront of a near-infrared (NIR, λ=800 nm) driver in harmonic generation. The preservation of spatiotemporal coherence in harmonic generation enables the transfer of the spatial beam distribution from the NIR driver to the DUV third harmonics. By irradiating spatially modulated NIR from a spatial light modulator (SLM) onto crystalline solids, the generated third harmonic DUV patterns were manipulated into desired forms, including a high-visibility sinusoidal distribution with a real-time adjustable pitch, angle, and phase. Our technique facilitates precision DUV optical metrology and DUV structured illumination microscopy.