Lithium niobate (LN) is one of the most sought‐after materials for nanophotonic devices, including frequency converters, modulators, and quantum light sources. Integration of LN into optical devices, however, is hampered by significant top‐down fabrication challenges due to its exceptional chemical resistance. Scalable fabrication methods that preserve material quality while reducing fabrication complexity and cost are, therefore, crucial to advancing LN devices. A photochemical metal–organic decomposition technique is presented for the scalable patterning of LN at ambient conditions, eliminating the need for harsh etching conditions and cleanroom protocols. The method utilizes a solution of a custom‐prepared photosensitive organometallic precursor as a negative photoresist. The ultraviolet (UV) light exposure of the thin films of the precursor through a photomask, followed by rinsing with ethanol, yields amorphous patterns, which transform into crystalline LN after a calcination step. This method enables a scalable fabrication of a range of complex geometric shapes with a feature resolution down to 30 μm. The patterned LN metasurfaces exhibit a tunable second harmonic generation activity with an isotropic optical response. This approach offers a scalable and low‐cost pathway for manufacturing LN photonics and the potential to fabricate other materials (e.g., barium titanate and lithium tantalate).
Ali et al. (Sun,) studied this question.