We review the current status of single-photon-source and single-photon-detector technologies operating at wavelengths from the ultraviolet to the infrared. We discuss applications of these technologies to quantum communication, a field currently driving much of the development of single-photon sources and detectors.

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Invited review article: Single-photon sources and detectors

Avalanche photodiodes, which operate above the breakdown voltage in Geiger mode connected with avalanche-quenching circuits, can be used to detect single photons and are therefore called singlephoton avalanche diodes SPAD's. Circuit configurations suitable for this operation mode are critically analyzed and their relative merits in photon counting and timing applications are assessed. Simple passive-quenching circuits (PQC's), which are useful for SPAD device testing and selection, have fairly limited application. Suitably designed active-quenching circuits (AQC's) make it possible to exploit the best performance of SPAD's. Thick silicon SPAD's that operate at high voltages (250-450 V) have photon detection efficiency higher than 50% from 540- to 850-nm wavelength and still ~3% at 1064 nm. Thin silicon SPAD's that operate at low voltages (10-50 V) have 45% efficiency at 500 nm, declining to 10% at 830 nm and to as little as 0.1% at 1064 nm. The time resolution achieved in photon timing is 20 ps FWHM with thin SPAD's; it ranges from 350 to 150 ps FWHM with thick SPAD's. The achieved minimum counting dead time and maximum counting rate are 40 ns and 10 Mcps with thick silicon SPAD's, 10 ns and 40 Mcps with thin SPAD's. Germanium and III-V compound semiconductor SPAD's extend the range of photon-counting techniques in the near-infrared region to at least 1600-nm wavelength.

Avalanche photodiodes and quenching circuits for single-photon detection

Geiger-mode avalanche photodiodes (G-APDs) have been developed during recent years and promise to be an alternative to photomultiplier tubes. They have many advantages like single photon response, high detection efficiency, high gain at low bias voltage and very good timing properties but some of their properties, the dark count rate for example, can be a problem. Several types of G-APDs are on the market and should be selected carefully for a given application.

Geiger-mode avalanche photodiodes, history, properties and problems

Semiconductor photodiodes were developed in the early `Forties approximately at the time when the photomultiplier tube became a commercial product (RCA 1939) Only in recent years, with the invention of the Geiger-mode avalanche photodiodes, have the semiconductor photo detectors reached sensitivity comparable to that of photomultiplier tubes The evolution started in the `Sixties with the p-i-n (PIN) photodiode, a very successful device, which is still used in many detectors for high energy physics and a large number of other applications like radiation detection and medical imaging The next step was the development of the avalanche photodiode (APD) leading to a substantial reduction of noise but not yet achieving single photon response The weakest light flashes that can be detected by the PIN diode need to contain several hundreds of photons An improvement of the sensitivity by 2 orders of magnitude was achieved by the development of the avalanche photodiode, a device with internal gain At the end of the millennium, the semiconductor detectors evolved with the Geiger-mode avalanche photodiode into highly sensitive devices, which have an internal gain comparable to the gain of photomultiplier tubes and a response to single photons A review of the semiconductor photo detector design and development, the properties and problems, some applications and a speculative outlook on the future evolution will be presented

https://iopscience.iop.org/article/10.1088/1748-0221/4/04/P04004/pdf

Advances in solid state photon detectors

The evolution of solid-state avalanche detectors of single optical photons is outlined and the issues for further progress are discussed. Physical phenomena that underlay the operation of the single-photon avalanche diodes (SPAD) and determine the performance are considered and their role is assessed (detection efficiency; dark-counting rate; afterpulsing; photon timing resolution; etc.). The main technological issues that hamper the development of detectors with wide sensitive area and of array detectors with high filling factor are illustrated. Silicon SPADs are the main focus of attention; infrared-sensitive SPADs in germanium and in compound semiconductors are also dealt with. The role of the active-quenching circuits (AQC) is assessed and the evolution is outlined up to integrated AQCs, which offer the prospect of monolithic integration of complete photon counter instruments.

/pdf/evolution-and-prospects-for-single-photon-avalanche-diodes-403hxwt2fs.pdf

Evolution and prospects for single-photon avalanche diodes and quenching circuits

We have investigated for the first time the propagation of the avalanche multiplication over the area of p‐n junctions reverse biased above the breakdown voltage. The multiplication process spreads from the point where the avalanche is triggered to the whole junction area with a speed proportional to the final steady‐state value of the avalanche current. The values of the propagation speed suggest that the phenomenon is due to diffusion of carriers assisted by avalanche multiplication. This effect strongly affects the rise of the avalanche current and turns out to limit the performance of single photon avalanche diodes.

Observation of avalanche propagation by multiplication assisted diffusion in p-n junctions

Time-correlated photon counting with solid state detectors is of considerable interest for high resolution optical time-domain reflectometry (OTDR). Up to now long measurement times were required. A new approach is described, yielding measurement times 50 times shorter and dynamic range enhanced by ≈ 20dB

Photon-timing OTDR: a multiphoton backscattered pulse approach

A position-sensitive photodiode of new concept is introduced. The device is operated biased above the breakdown voltage in the so-called Geiger mode. The absorption of a single photon results in a mA-range avalanche pulse. The time and position (one coordinate) information of the photon arrival are carried by the avalanche current leading edge. The physics of the device operation is discussed: constraints in the device design are derived. Experimental measurements on silicon test structures with a position-sensitive area of 70 by 14 μm2 are presented. Spatial resolution better than 10 μm FWHM (full width at half maximum), limited by the spot size of the light beam, and temporal resolution better than 100 ps FWHM are demonstrated.

S. Vanoli

Papers

Observation of avalanche propagation by multiplication assisted diffusion in p-n junctions

Photon-timing OTDR: a multiphoton backscattered pulse approach

(PS)2: a new semiconductor device for positron-sensitive picosecond detection of single optical photons