Boosting classical and quantum nonlinear processes in ultrathin van der Waals materials.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40442079.
- Also identified by DOI 10.1038/s41467-025-58449-3 and PMC identifier 12122887.
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Abstract
Understanding and controlling nonlinear processes is crucial for engineering light-matter interaction and generating non-classical light. A significant challenge in ultra-thin nonlinear materials is the marked diminution of the nonlinear conversion efficiency due to the reduced light-matter interaction length and, in many cases, the centrosymmetric crystalline structures. Here we relax these limitations and report a giant boost of classical and quantum nonlinear processes in ultrathin van der Waals materials. Specifically, with a metal-nonlinear material heterostructure we enhance classical second-harmonic generation in h-BN flakes by two orders of magnitude. Moreover, we have engineered a metal-SiO<sub>2</sub>-nonlinear material heterostructure resulting in a remarkable two orders of magnitude augmentation of the quantum spontaneous parametric down-conversion (SPDC) in NbOCl<sub>2</sub> flakes. Notably, we demonstrate SPDC in a 16 nm-thick NbOCl<sub>2</sub> flake integrated into the proposed structure. These findings simplify on-chip quantum state engineering and accelerate the use of van der Waals materials in nonlinear optoelectronics.