Academic Editors: Yuxi Ruan, Bin Liu
and Yuanlong Fan
Received: 18 July 2025
Revised: 12 August 2025
Accepted: 28 August 2025
Published: 3 September 2025
Citation: Levine, Z.H.; Bienfang, J.C.;
Migdall, A.L.; Zimmerman, N.M. A
Metrological Near-Room-Temperature
Photon-Number-Resolving Detector:
A Design Study. Sensors 2025, 25, 5470.
https://doi.org/10.3390/s25175470
Copyright: © 2025 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license
(https://creativecommons.org/
licenses/by/4.0/).
Article
A Metrological Near-Room-Temperature Photon-Number-
Resolving Detector: A Design Study
Zachary H. Levine
1,
* , Joshua C. Bienfang
1
, Alan L. Migdall
1,2
and Neil M. Zimmerman
3
1
Quantum Measurement Division, National Institute of Standards and Technology,
Gaithersburg, MD 20899-8410, USA; joshua.bienfang@nist.gov (J.C.B.); migdall@nist.gov (A.L.M.)
2
Joint Quantum Institute, College Park, MD 20742-0001, USA
3
Nanoscale Device Characterization Division, National Institute of Standards and Technology,
Gaithersburg, MD 20899-8423, USA; neil.zimmerman@nist.gov
* Correspondence: zlevine@nist.gov
Abstract
We describe and model a non-cryogenic optical detector designed to count incident photons
with metrological accuracy. Our design consists of a semiconductor device operating at
−
10
◦
C and is predicted to resolve pulses of up to 10 photons with an error rate of 2% in
the input number of photons. We present an estimate of the overall device performance
using a combination of estimates and simulations of optical loss, discrete electron loss and
noise, and electronic noise.
Keywords: photon counting; room-temperature silicon device; low error rate
1. Introduction
An optical detector with metrological-grade photon-number error rate (i.e., a high
probability that the detector output correctly reports the number of photons incident on
its input) not only represents a primary standard for optical-power calibration, but also
provides a critical enabling technology for photonic quantum information science [
1
–
6
].
Unfortunately, achieving low photon-number error rate in real-world devices is uniquely
challenging because it requires both low noise and high single-photon system detection
efficiency, as well as high photon-number resolution. These challenges only increase as the
photon number increases. For example, a device with single-photon detection efficiency of
99% (1% error rate) has a 10 photon error rate of nearly 10%. Typically, the technologies
that provide the highest single-photon detection efficiency (typically, 99%) have required
cryogenic cooling, to 1 K or lower. On the other hand, detectors that operate near room
temperature do not reach the highest detection efficiencies or either do not provide clear
photon-number resolution [7] or provide very limited photon-number resolution [8,9].
The ability to detect single photons does not necessarily imply the ability to have a
photon-number resolving (PNR) device. For example, consider single-photon avalanche
detectors (SPADs) and microchannel plates. For such systems, although single photons can
be detected, the noise inherent in the first step of the avalanche process—it could yield two
or three or more electrons—means that these have not been candidates as PNR detectors to
date, at least not as single devices.
As a result, one common method to achieve some degree of photon-number resolution
is to multiplex non-PNR detectors to form a quasi-PNR detector [
10
,
11
]. Unfortunately,
this approach is inherently limited by the fact that there is always a non-zero probability
that multiple photons will end up at the same non-PNR detector, and the fact that the noise
Sensors 2025, 25, 5470 https://doi.org/10.3390/s25175470
