Physicists convert microwaves to light using magnetic semiconductor

Physicists at The City College of New York have demonstrated a method to convert microwave signals into light using a layered magnetic compound semiconductor known as CrSBr. This development, published in Nature Materials, provides a potential bridge for quantum networks by linking microwave-based quantum processors with optical fiber communication networks.

The process utilizes the coupling between magnons (magnetic waves) and excitons (electron-hole pairs). When the CrSBr crystal is driven by microwaves, the resulting magnetic motion modulates reflected laser light, creating a coherent optical signal. The conversion was observed across a microwave frequency window of approximately 300MHz, and the operating frequency can be tuned via an applied magnetic field.

While the current efficiency is not yet sufficient for practical quantum networking, the research establishes a new physical mechanism for transduction. Future improvements using thinner crystals, resonators, or polariton engineering could enhance the conversion capabilities required to transfer quantum information over long distances.