15.01.2025

A study published in Nature Photonics demonstrates the generation of quantum photons using nanoengineered two-dimensional materials. | New paper in "Nature Photonics".

Nanoscale-engineered two-dimensional semiconductors can be programmed to efficiently produce photons on ultracompact spatial scales. This is the result of a recent study on nonlinear and quantum optics published in Nature Photonics. The materials were built and programmed in a collaboration between Columbia University in New York City (USA), the Polytechnic University of Milan in Italy, and the University of Chicago (USA). While the quantum nature of the generated photons was demonstrated at the University of Vienna.

Photons lie at the heart of many emerging quantum technologies, such as computing, cryptography, and metrology. One approach to generate photons is to convert higher-energy classical laser light into two lower-energy quantum photons in a nonlinear crystal. However, conventional crystals have thicknesses of a few millimeters, or even centimeters, limiting their miniaturization and compatibility with integrated optical devices. This miniaturization is an essential step to making practical quantum devices. Thinning down standard nonlinear crystals greatly reduces the efficiency of producing photons.

The recent discovery of two-dimensional materials, such as transition metal dichalcogenides (TMDs), has introduced exciting new possibilities in the miniaturization of photonic devices. TMDs are layered materials that are transforming the field of nonlinear optics due to their large optical nonlinearity. Moreover, these materials can be "programmed" by precisely stacking layers of TMDs into tiny pyramids. When done properly, this makes the process more efficient, enhancing the creation of photons with desired properties.

According to Lee Rozema, a Senior Scientist at the University of Vienna, "Our work shows that ultrathin two-dimensional materials can be nanoengineered to efficiently produce photon pairs. In the future, we hope to show that this can also enhance the entanglement between the photons, opening a new platform for quantum optics."

Miniaturizing photon sources is one of the main challenges of photonic quantum computing. This miniaturized and programmable source paves the way for ultracompact quantum technologies and may influence the future of secure communication, photonic quantum computing, and a variety of other emerging quantum technologies.

Chiara Trovatello, Carino Ferrante, Birui Yang, Josip Bajo, Benjamin Braun, Zhi Hao Peng, Xinyi Xu, Philipp K. Jenke, Andrew Ye, Milan Delor, D. N. Basov, Jiwoong Park, Philip Walther, Cory R. Dean, Lee A. Rozema, Andrea Marini, Giulio Cerullo & P. James Schuck

Quasi-phase-matched up- and down-conversion in periodically poled layered semiconductors

Nature Photonics (2025).