Chalmers researchers combine two photonics fields in nanodisk

Researchers at the Department of Physics at Chalmers University of Technology have successfully combined two major research fields in photonics—nonlinear and high-index nanophotonics—into a single disk-shaped nano-object. The new nanodisk enables efficient light frequency conversion in a compact form.

Photonic applications, which leverage light-matter interactions, are crucial for technologies in communications, medicine, and laser systems. The development of nanodisks aims to enhance the performance of these technologies. The nanodisk developed by the researchers is smaller than the wavelength of light but acts as a highly efficient light frequency converter, exhibiting up to 10,000 times greater efficiency than unstructured material.

The research utilized transition metal dichalcogenide (TMD), specifically molybdenum disulfide, an atomically thin material with exceptional optical properties at room temperature. A key challenge was preserving the material's nonlinear properties during fabrication, as it is sensitive to crystalline lattice symmetry constraints. The Chalmers researchers have developed a method to fabricate the nanodisk while maintaining and even enhancing these properties.

The new nanodisk combines extreme nonlinearity with a high refractive index in a compact structure. Researchers state that this material and design represent "state-of-the-art" and could be attractive to industry. "It really is a milestone, particularly due to the disk's extremely small size," says Professor Timur Shegai. Traditional platforms utilizing these phenomena are typically centimeter-scale, while the nanodisk is only about 50 nanometers.

This development is expected to advance nonlinear nanophotonics research, potentially enabling future experiments in both quantum and classical photonics. By nanostructuring this unique material, the size of optical devices can be dramatically reduced while increasing their efficiency, leading to applications in nonlinear optics and the generation of entangled photon pairs.