The various embodiments described herein include methods, devices, and systems for fabricating and operating superconducting photon detectors. In one aspect, a photon detector includes: (1) a first waveguide configured to guide photons from a photon source; (2) a second waveguide that is distinct and separate from the first waveguide and optically-coupled to the first waveguide; and (3) a superconducting component positioned adjacent to the second waveguide and configured to detect photons within the second waveguide.

A photoelectric conversion device according to an embodiment of the present disclosure includes an avalanche photodiode, a pulse generation unit that converts an output from the avalanche photodiode into a pulse signal, a pulse count unit that counts the pulse signal and outputs a pulse count value, a time count unit that outputs a time count value indicating a time from the start of operation of the pulse generation unit, an output unit that, when the pulse count value does not exceed a threshold value, outputs the pulse count value, and when the pulse count value exceeds the threshold value, ends counting in the pulse count unit and outputs the time count value at the time of the pulse count value exceeding the threshold value, and a threshold calculation unit that calculates the threshold value using the time count value.

A device includes a conversion unit, a generation unit configured to generate a pulse signal based on a signal from the conversion unit, a counter circuit configured to count the generated pulse signal, and a time measurement circuit configured to measure a time wherein one of a count value counted by the counter circuit or a time measurement value measured by the time measurement circuit is selectively output.

The present disclosure relates to limitation of noise on light detectors using an aperture. One example embodiment includes a system. The system includes a lens disposed relative to a scene and configured to focus light from the scene onto a focal plane. The system also includes an aperture defined within an opaque material disposed at the focal plane of the lens. The aperture has a cross-sectional area. In addition, the system includes an array of light detectors disposed on a side of the focal plane opposite the lens and configured to intercept and detect diverging light focused by the lens and transmitted through the aperture. A cross-sectional area of the array of light detectors that intercepts the diverging light is greater than the cross-sectional area of the aperture.

An exemplary wearable brain interface system includes a head-mountable component and a control system. The head-mountable component includes an array of photodetectors that includes a photodetector comprising a single-photon avalanche diode (SPAD) and a fast-gating circuit configured to arm and disarm the SPAD. The control system is for controlling a current drawn by the array of photodetectors.

To control an excess bias to an appropriate value in a light detection device. A solid-state image sensor includes a photodiode, a resistor, and a control circuit. In this solid-state image sensor, the photodiode photoelectrically converts incident light and outputs a photocurrent. Furthermore, in the solid-state image sensor, the resistor is connected to a cathode of the photodiode. Furthermore, in the solid-state image sensor, the control circuit supplies a lower potential to an anode of the photodiode as a potential of the cathode of when the photocurrent flows through the resistor is higher.

Described herein is an electronic device, including a pixel and a turn-off circuit. The pixel includes a single photon avalanche diode (SPAD) having a cathode coupled to a high voltage node and an anode selectively coupled to ground through an enable circuit, and a clamp diode having an anode coupled to the anode of the SPAD and a cathode coupled to a turn-off voltage node. The turn-off circuit includes a sense circuit coupled between the turn-off voltage node and ground and configured to generate a feedback voltage, and a regulation circuit configured to sink current from the turn-off voltage node to ground based upon the feedback voltage such that a voltage at the turn-off voltage node maintains generally constant.

An illustrative optical measurement system includes a light source configured to emit a light pulse directed at a target. The optical measurement system further includes a control circuit configured to drive the light source with a current pulse comprising a non-linear rise, and a decline from a maximum output to zero having a duration within a threshold percentage of a total pulse duration of the current pulse.

Conventional readout of a superconducting nanowire single-photon detector (SNSPD) sets an upper bound on the output voltage to be the product of the bias current and the load impedance, I.sub.B×Z.sub.load, where Z.sub.load is limited to 50Ω in standard RF electronics. This limit is broken/exceeded by interfacing the 50Ω load and the SNSPD using an integrated superconducting transmission line taper. The taper is a transformer that effectively loads the SNSPD with high impedance without latching. The taper increases the amplitude of the detector output while preserving the fast rising edge. Using a taper with a starting width of 500 nm, a 3.6× higher pulse amplitude, 3.7× faster slew rate, and 25.1 ps smaller timing jitter was observed. The taper also makes the detector's output voltage sensitive to the number of photon-induced hotspots and enables photon number resolution.

High speed, and high timing resolution photon detecting systems and methods are presented with multiplication and self-quenching and self-recovering functions.