Photon number measurement using heterodyne method for a detector's quantum efficiency determination based on...

Area of Science:

• Quantum Information Science
• Quantum Optics
• Metrology

Background:

• Accurate characterization of single photon detectors is essential for advancing quantum information technologies, including quantum computers and quantum key distribution.
• Detection efficiency is a critical parameter for single photon detectors.
• The reference-free twin-photon-based Klyshko method is a standard technique for measuring detection efficiency, but its signal-to-noise ratio (SNR) can be limited by noise.

Purpose of the Study:

• To address the low signal-to-noise ratio (SNR) encountered in standard Klyshko method measurements for single photon detector characterization.
• To propose and validate a novel heterodyne-based method for enhancing SNR in detection efficiency measurements.

Main Methods:

• Implementation of a heterodyne detection scheme within the standard Klyshko measurement setup.
• Introduction of modulation at a higher frequency to facilitate averaging, circumventing low-frequency 'random telegraph signal' noise.
• Numerical simulation and experimental validation of the proposed heterodyne-based method.

Main Results:

• The proposed heterodyne-based method demonstrated a significant improvement in signal-to-noise ratio (SNR) compared to simple averaging techniques.
• Numerical simulations indicated a 14-fold increase in SNR.
• Experimental results confirmed the 14-fold SNR improvement, validating the effectiveness of the new method.

Conclusions:

• The heterodyne-based method offers a robust solution for improving SNR in single photon detector efficiency measurements using the Klyshko technique.
• This advancement is vital for the precise parameter characterization required for developing sophisticated quantum informational components.
• The validated method provides a pathway to more reliable and accurate measurements in quantum metrology.