Optical frequency conversion in bulk nonlinear crystals is crucial for applications spanning extreme ultraviolet to THz waves, contributing to many fields of science and technology. However, existing nonlinear materials impose significant limitations on integration, miniaturization, and nonlinear interaction control, restricting technological advancement. Recent breakthroughs in nonlinear metasurfaces have demonstrated unprecedented nonlinear properties, vastly outperforming bulk crystals. However, their two-dimensional nature and nanoscale thickness limit their conversion efficiency, with no existing method to overcome these constraints. This project aims to bridge this gap by developing a new class of 3D nano-engineered nonlinear materials. This approach will enhance nonlinear interactions beyond current materials, paving the way for highly efficient, miniaturized optical devices. The expected impacts of the project include: Enhancing Frequency Conversion Efficiency – Achieving superior conversion efficiencies over bulk crystals. Advancing Nanofabrication – Developing scalable, technologically viable 3D nanostructures. Enabling Miniaturization – Creating compact, integrable optical components.