High-Temperature Single-Photon Detectors using Iron-Chalcogenide Superconductors

Non-Technical Abstract:

Detecting single photons - the quanta of light- is the cornerstone of cutting-edge quantum technologies such as optical quantum computing, communication, and ultra-sensitive imaging. Superconducting nanowire single-photon detectors (SNSPDs) have emerged as the leading single photon detection technology owing to their near-unity quantum efficiency, higher count rates, extremely low dark counts, and high timing resolution.

However, most state-of-the-art SNSPD detectors operate at very low temperatures (< 4 K), necessitating extensive cryo-cooling. Here, we propose utilizing high-temperature iron-based superconductors such as Fe(Te, Se), which is known to exhibit superconductivity up to 65 K at the monolayer limit, to advance single photon detection technology. This project aims to develop SNSPDs that operate at temperatures above liquid helium, significantly reducing the footprint and enhancing accessibility and scalability.

The project's success could advance the quantum technology revolution due to its higher working temperature regime, which may have critical applications in biomedical research, deep space imaging, and optical-quantum computing. Developing next-generation high-temperature SNSPDs will advance quantum technologies (National Quantum Initiative Act 2018) and integrated quantum photonics (CHIPS and Science Act, 2022).

This interdisciplinary project will enhance our science education initiatives and workforce development for the quantum age by providing hands-on quantum research experiences for students from K12 to undergraduate levels. Technical Abstract:

The project consists of three aims. The first aim focuses on the optical and transport properties of few-layered Fe(Te,Se) flakes. Low-temperature spectroscopy and transport measurements will be conducted to characterize the influence of thickness, temperature, and substrate on the superconducting properties of nanometer-thin Fe(Te, Se) flakes.

In the second aim, the nanofabrication and transport measurement of Fe(Te,Se) strips of varying widths (100 nm – 10μm) will be conducted to shed light on the microscopic mechanisms of photodetection in Fe(Te,Se). The third aim focuses on the optical characterization and single-photon detection of Fe(Te,Se) nanowires. The parameters of Fe(Te,Se) detectors, such as quantum efficiency, dark count, and count rates, will be quantified.

This research project is integrated with quantum science education and workforce development. Students from K-12 to undergraduate levels will have the opportunity to gain research experience in the quantum technology laboratory.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.