# VCI2019 - The 15th Vienna Conference on Instrumentation

18-22 February 2019
Vienna University of Technology
Europe/Vienna timezone

## Using Quantum Entangled Photons to Measure the Absolute PDE of a Multi-Pixel SiPM Array

21 Feb 2019, 17:20
20m
EI9

Talk SiPM

### Speaker

Dr Jamie Williams (University of Leicester)

### Description

Spontaneous parametric down-conversion (SPDC) of a visible pump photon is the generation of two less energetic, quantum entangled photons (QEPs), often in the near infrared (NIR), using a non-linear crystal such as beta barium borate (BBO). Since the detection of one QEP predicates the existence of its entangled twin, QEPs have previously been used to measure the absolute photon detection efficiency (PDE), η(λ), of a detector under test (DUT) by measuring time-coincident events with an additional trigger detector, allowing evaluation of $η_{DUT}$ (λ) without recourse to a calibrated reference detector.
We propose an extension of this technique to measure η(λ) for pixels on a multi-pixel array where each pixel provides an individual signal output, and we model this using Monte Carlo simulations. By treating all pixels in a multi-pixel array as indistinguishable, we show that the symmetry of the measurement allows the mean η(λ) of the array to be evaluated.
We describe the QEP absolute PDE measurement technique, and present the first experimental results showing the measurement of η(λ) for a 64-pixel SiPM array utilising a 64-channel waveform digitiser module to provide photon timing and coincidence measurements. We consider the feasibility of using QEPs for η(λ) measurements across the visible spectrum by using higher energy pump photons and considering coincident events in non-symmetric pixels, with the goal of developing an instrument for in-situ absolute PDE calibration.

### Primary authors

Dr Jamie Williams (University of Leicester) Prof. Jon Lapington (University of Leicester) Dr Steven Leach (University of Leicester) Mr Connor Duffy (University of Leicester)

### Presentation Materials

 Absolute PDE Vienna talk.pdf Absolute PDE Vienna talk.pptx