Single Photon Characterisation

Tommaso Lunghi, Boris A. Korzh, Bruno Sanguinetti +1 more

We show a setup for characterising the efficiency of a single-photon-detector absolutely and with a precision better than 1%. Since the setup does not rely on calibrated devices and can be implemented with standard-optic components, it can be realised in any laboratory. Our approach is based on an Erbium-Doped-Fiber-Amplifier (EDFA) radiometer as a primary measurement standard for optical power, and on an ultra-stable source of spontaneous emission. As a proof of principle, we characterise the efficiency of an InGaAs/InP single-photon detector. We verified the correctness of the characterisation with independent measurements. In particular, the measurement of the optical power made with the EDFA radiometer has been compared to that of the Federal Institute of Metrology using a transfer power meter. Our approach is suitable for frequent characterisations of high-efficient single-photon detectors.

Peter J. Mosley, Christine Silberhorn, Alfred B. U’Ren +1 more

We propose a method of creating single photons in pure quantum states by parametric downconversion, along with the analysis of an experimental scheme for characterising their purity using multiple crystal interferometry.

Yan Liang, Heping Zeng

Callum Jones, Jolly Xavier, Samir Vartabi Kashanian +3 more

The time-dependent Mandel Q parameter, Q ( T ), provides a measure of photon number variance for a light source as a function of integration time. Here, we use Q ( T ) to characterise single photon emission from a quantum emitter in hexagonal boron nitride (hBN). Under pulsed excitation a negative Q parameter was measured, indicating photon antibunching at an integration time of 100 ns. For larger integration times Q is positive and the photon statistics become super-Poissonian, and we show by comparison with a Monte Carlo simulation for a three-level emitter that this is consistent with the effect of a metastable shelving state. Looking towards technological applications for hBN single photon sources, we propose that Q ( T ) provides valuable information on the intensity stability of single photon emission. This is useful in addition to the commonly used g (2) ( τ ) function for the complete characterisation of a hBN emitter.