Bright emission from hidden quantum states demonstrated in nanotechnology breakthrough

by Clarence Oxford
Los Angeles CA (SPX) Nov 13, 2025

Researchers at the City University of New York and the University of Texas at Austin have enabled the strong emission and direct control of previously hidden states of light called dark excitons in atomically thin semiconductor materials. This advancement, described in Nature Photonics, enables emission from dark excitons at the nanoscale and may facilitate faster, smaller, and more efficient devices.

Dark excitons, which exist in monolayer semiconductors, have long evaded detection by conventional optical methods due to weak light emission. They are valued for quantum computing and photonics as their properties include prolonged lifetimes and stability against environmental interference.

The research team engineered a nanoscale cavity by matching gold nanotubes with a single layer of tungsten diselenide (WSe2). The resulting structure increased emission from dark excitons by 300,000 times, making these quantum states detectable and tunable.

"This work shows that we can access and manipulate light-matter states that were previously out of reach," said principal investigator Andrea Alu of the CUNY Graduate Center. "By turning these hidden states on and off at will and controlling them with nanoscale resolution, we open exciting opportunities to disruptively advance next-generation optical and quantum technologies, including for sensing and computing."

The scientists demonstrated the ability to switch the dark exciton emission by applying electric and magnetic fields. This precise control supports further implementation in photonic circuitry and quantum information. The method preserves the intrinsic properties of the materials, while enabling significant enhancement of their optical response.

Jiamin Quan, first author, added: "Our study reveals a new family of spin-forbidden dark excitons that had never been observed before. This discovery is just the beginning - it opens a path to explore many other hidden quantum states in 2D materials."

The investigation resolves longstanding debate over whether plasmonic structures can enhance dark exciton emission without altering their quantum characteristics. The team accomplished this using thin boron nitride layers in their heterostructure.

Research Report:On-Site Enhancement and Control of Spin-Forbidden Dark Excitons in a Plasmonic Heterostructure