Vanadium dioxide-integrated valley photonic crystals for topological control of light

As computational technology needs increase, the demand for faster, smaller, and more robust devices faces the challenge of fundamental physical limitations. Much like semiconductors influence the flow of electrons to transmit information, photonic crystals manipulate the propagation of light, offering tight directional control and defect resistance. Furthermore, the precise fabrication of photonic crystals allows for integrated optical circuits with dimensions comparable to the wavelength of light. The unique band structure topology of valley photonic crystals allows for robust control of light based on its valley degree of freedom, leading to switchable optical paths and tight light propagation. In this work, we present preliminary fabrication techniques for vanadium dioxide-integrated valley photonic crystals that can tightly control light propagation and create switchable optical paths on a single chip. A hexagonal grid of alternating vanadium dioxide and germanium pillars were fabricated using electron beam lithography, electron beam deposition, and sputter deposition. This technology has potential applications in quantum information science and neural networks, where it can enhance the encoding and manipulation of information through multiple optical paths within integrated circuits.