Quantum Radiometry

The Quantum Radiometry research group investigates novel concepts for the detection, processing, and use of extremely weak photonic signals—from single photons to correlated and entangled quantum states. At the core of our work are superconducting nanowire single-photon detectors (SNSPDs) as a key technology for highly sensitive photonics, quantum systems, and secure information processing.

Our research connects photonics, quantum detection, and electronics into end-to-end system approaches for high-performance and energy-efficient photonic technologies. We not only develop detectors with the highest sensitivity, but also consider the entire functional chain—from the interaction of light with matter, through sensor-near and energy-efficient readout, to the intelligent processing of acquired data in novel hardware and computing architectures. Our goal is to combine ultrasensitive detection with adaptive and trustworthy information processing.

A particular focus lies at the interface of biophotonics, quantum technologies, and hardware-near artificial intelligence. Building on SNSPD-based detection platforms, we develop concepts that tightly couple photonic and electronic functionality. This approach also includes memristive and quantum-memristive devices as a foundation for future ultra-energy-efficient hardware for applications in medical diagnostics, the life sciences, and secure information processing.

Dr. Nan Du

Head of Working Group
+49 3641 206117
nan.du@leibniz-ipht.de

Selected Research Topics

Ultrafast detection of single photons with superconducting nanowire single-photon detectors (SNSPDs) featuring high efficiency, low dark count rate, and excellent timing resolution

Coupling of SNSPDs with quantum memristors for energy-efficient, hardware-near AI in medical diagnostics and the life sciences

Generation and detection of polarization-entangled photonic states for applications in quantum communication and secure communication systems

Application Areas

Detection

We develop platforms for the acquisition of extremely weak optical signals based on superconducting nanowire single-photon detectors (SNSPDs). The focus is on the physical processes of signal generation as well as on optimizing detection efficiency, dark count rate, timing resolution, count rate, and polarization dependence. Another focus is on integrated and array-based single-photon detectors for applications in biophotonics, quantitative spectroscopy, and quantum technology.

Energy

We investigate how ultrasensitive photon detection can be combined with novel photonic and electronic devices to form energy-efficient overall systems. The emphasis is on the close integration of detection, readout, signal processing, and intelligent data processing. To this end, we develop concepts at the interface of SNSPDs, waveguides, and quantum-memristive devices for in-memory computing, adaptive signal processing, and hardware-near AI. The goal is to create cost-effective ultra-low-power systems for medical diagnostics and the life sciences.

Security

The group develops concepts for trustworthy photonic and quantum-technological systems. SNSPDs serve as a key enabling technology for quantum key distribution (QKD), photonic quantum networks, and the detection of nonclassical states of light. The focus is on polarization dependence, device-related variations, and coupling effects in optical receiver modules. In addition, the group works on entanglement generation and precise single-photon detection for secure communication and new quantum-based hardware concepts.

Application Examples

Ultrasensitive biophotonics and medical diagnostics

Hardware-near neuromorphic systems

Secure quantum communication and quantum key distribution

SEM images of four NbN-based SNSPD pixels