The demand for increasingly sensitive light detectors fuels advances in optical computing, communication and technologies reliant on correlated photons, but accurately measuring detector performance presents a significant challenge. Leif Albers, Jan-Malte Michaelsen, and Roman Schnabel, all from Universität Hamburg, now demonstrate a novel radiometric calibration method that directly addresses this need. Their approach, grounded in the principles of squeezed light and Heisenberg’s uncertainty principle, offers an in-situ calibration, simultaneously determining both detection efficiency and a more exacting measure of performance at the specific frequencies relevant to the user’s application. By calibrating commercially available photodiodes at 1550nm using squeezed vacuum states, the team achieves an impressive (97.20 + 0.37)% system detection efficiency, while also revealing that current photodiode efficiencies fall short of the requirements for emerging technologies like gravitational wave detectors and optical computers.
Researchers from Universität Hamburg have now demonstrated a novel radiometric calibration method that directly addresses this need. Their approach, grounded in the principles of squeezed light and Heisenberg’s uncertainty principle, offers an in-situ calibration, simultaneously determining both detection efficiency and a more exacting measure of performance at the specific frequencies relevant to the user’s application. By calibrating commercially available photodiodes at 1550nm using squeezed vacuum states, the team achieves an impressive system detection efficiency of 97.37%, while also revealing that current photodiode efficiencies fall short of the requirements for emerging technologies like gravitational wave detectors and optical computers.,.
Squeezed Light Calibrates Photodiode Quantum Efficiency
Scientists pioneered a novel quantum radiometric calibration (QRC) method to precisely determine the detection and quantum efficiencies of photodiodes, essential components for emerging optical quantum technologies. Recognizing the limitations of existing calibration techniques, the team developed an in situ approach founded on the principles of squeezed light and Heisenberg’s uncertainty principle. This method moves beyond traditional calibration relying on external standards, instead directly assessing photodiode performance within the operating environment. The study harnessed 10-dB-squeezed vacuum states of light to calibrate a pair of commercially available photodiodes at a wavelength of 1550nm.
Researchers meticulously measured the escape efficiency of their squeezing resonator, achieving a value of 98.3%, enabling accurate determination of the photodiodes’ detection efficiency at 97.37% and quantum efficiency at 96.4% under a specified angle of incidence. To further refine the measurement, the team implemented retro-reflection, increasing the efficiencies.
The study meticulously defined detection efficiency and quantum efficiency, establishing a clear framework for evaluating photodiode performance. The team’s innovative approach allows for direct calibration of photodiodes as primary standards, bypassing the need for complex calibration chains. The results reveal that currently available photodiode efficiencies at 1550nm are unexpectedly low, falling short of the requirements for future gravitational wave detectors and optical quantum computing applications.,.
Squeezed Light Enables Precise Photodiode Calibration
This work presents a novel radiometric calibration method leveraging squeezed light and the Heisenberg uncertainty principle, establishing a new standard for precise photodiode characterization. The researchers successfully calibrated a pair of commercially available photodiodes at 1550nm, achieving a system detection efficiency of 97.37%. This calibration was performed directly at the user application’s measurement frequencies, offering a significant advantage over existing methods. The core of this achievement lies in the utilization of 10-dB-squeezed vacuum states, which enable in situ calibration and simultaneous determination of both detection efficiency and quantum efficiency.
Experiments demonstrate the ability to measure photodiodes with unprecedented accuracy, revealing that currently available efficiencies at 1550nm are unexpectedly low. This finding has critical implications for the development of future gravitational wave detectors and optical computing technologies, both of which demand photodiodes capable of detecting approximately 10^16 photons per second with near-perfect efficiency. By employing squeezed states of light, the researchers effectively reduced quantum noise, allowing for a more accurate determination of photodiode performance. This breakthrough delivers a new pathway for characterizing detectors, paving the way for advancements in quantum technologies and high-precision measurements. The results confirm a need for improved photodiode efficiencies to meet the demanding requirements of next-generation scientific instruments.,.
Squeezed Light Enables Precise Photodiode Calibration
Researchers have introduced a new technique for calibrating photodiodes—key components in many quantum technologies—with unprecedented precision. The method, known as Quantum Radiometric Calibration (QRC), exploits squeezed light and the limits imposed by Heisenberg’s uncertainty principle to directly measure both detection efficiency and quantum efficiency at application-specific frequencies. Unlike conventional calibration approaches, QRC operates in situ, providing performance assessments under realistic operating conditions.
Applying QRC to commercially available photodiodes at a wavelength of 1550 nm, the researchers achieved an absolute calibration uncertainty of just 0.37%. The measurements revealed detection and quantum efficiencies of 97.20% and 96.9%, respectively. While these values are determined with exceptional precision, they fall short of the stringent requirements needed for next-generation quantum technologies, including continuous-variable optical quantum computers and the planned Einstein Telescope for gravitational-wave detection.
The results highlight a critical bottleneck: current photodiode efficiencies are insufficient to support fault-tolerant operation in several advanced quantum systems. By clearly identifying this limitation, the study underscores the need for improved photodiode designs and materials. The authors emphasize that QRC provides a powerful new tool for both researchers and manufacturers, enabling accurate, application-relevant benchmarking of photodiode performance and guiding future improvements.Ultimately, Quantum Radiometric Calibration is expected to play an important role in the development of fault-tolerant optical quantum technologies, offering a robust path toward the higher detection efficiencies required for scalable quantum systems.
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🗞 Quantum Radiometric Calibration
🧠 ArXiv: https://arxiv.org/abs/2512.14947
