In an embodiment, an arc light sensor includes: a first polarizer, a second polarizer, a magneto-optical material, a first light filter and a processing unit. The first polarizer is used for polarizing incident first target light, to form first polarized light in a first polarization direction. The second polarizer is used for polarizing incident second target light, to form second polarized light in the first polarization direction. The magneto-optical material, in a current magnetic field, uses the current magnetic field to rotate a polarization direction of the first polarized light, to form third polarized light. The first light filter is used for filtering the third polarized light, to form fourth polarized light capable of passing in a second polarization direction. The processing unit is used for determining whether the second target light is arc light according to intensity of the second polarized light and intensity of the fourth polarized light.

A system for detecting an illuminance of the present invention includes a light source, a light sensor, and a signal output module. The light source includes a first A light-emitting diode, the first A light-emitting diode having a first color light; and the light source emits a first ray of light. The light sensor has a sensing face; the light sensor includes a first B light-emitting diode disposed on the sensing face, the first B light-emitting diode having the first color light; and the light sensor receives at least a portion of the first ray of light and generates a first sensing voltage. The signal output module is coupled to the light sensor to receive the first sensing voltage and output a sensing result signal according to the first sensing voltage.

Methods, systems, and apparatus, for a stray-light testing station. In one aspect, the stray-light testing station includes an illumination assembly including a spatially extended light source and one or more optical elements arranged to direct a beam of light from the spatially extended light source along an optical path to an optical receiver assembly including a lens receptacle configured to receive a lens module and position the lens module in the optical path downstream from the parabolic mirror so that the lens module focuses the beam of light from the spatially extended light source to an image plane, and a moveable frame supporting the optical receiver assembly including one or more adjustable alignment stages to position the optical receiver assembly relative to the illumination assembly such that the optical path of the illumination assembly is within a field of view of the optical receiver assembly.

An example circuit includes a light detector and a biasing capacitor having (i) a first terminal that applies to the light detector an output voltage that can either bias or debias the light detector and (ii) a second terminal for controlling the output voltage. The circuit includes a first transistor connected to the second terminal of the biasing capacitor and configured to drive the output voltage to a first voltage level above a biasing threshold of the light detector and thereby biasing the light detector. The circuit includes a second transistor connected to the second terminal of the biasing capacitor and configured to drive the output voltage to a second voltage level below the biasing threshold of the light detector and thereby debiasing the light detector. The second voltage is a non-zero voltage that corresponds to a charge level of the biasing capacitor.

Deformable optoelectronic devices are provided, including photodetectors, photodiodes, and photovoltaic cells. The devices can be made on a variety of paper substrates, and can include a plurality of fold segments in the paper substrate creating a deformable pattern. Thin electrode layers and semiconductor nanowire layers can be attached to the substrate, creating the optoelectronic device. The devices can be highly deformable, e.g. capable of undergoing strains of 500% or more, bending angles of 25 or more, and/or twist angles of 270 or more. Methods of making the deformable optoelectronic devices and methods of using, e.g. as a photodetector, are also provided.

An optical power monitoring device that monitors power of input light reflected back into an optical fiber among output light output from the optical fiber, the optical power monitoring device includes: a photodetector disposed by the optical fiber that detects Rayleigh scattered light generated by the input light and the output light that are guided by the optical fiber; and a calculator that performs a calculation to exclude a component that corresponds to an output of the output light detected by the photodetector using first information that indicates a relationship between an output of the output light obtained in advance under a condition where the output light is not reflected and the output of the output light detected by the photodetector.

The various embodiments described herein include methods, devices, and systems for fabricating and operating photodetector circuitry. In one aspect, a photon detector system includes: (1) a first superconducting wire having a first threshold superconducting current; (2) a second superconducting wire having a second threshold superconducting current; (3) a resistor coupled to the first wire and the second wire; (4) current source(s) coupled to the first wire and configured to supply a current that is below the second threshold current; and (3) a second circuit coupled to the second wire. In response to receiving light at the first wire, the first wire transitions from a superconducting state to a non-superconducting state. In response to receiving light at the second wire while the first wire is in the non-superconducting state, the second wire transitions to a non-superconducting state, redirecting the first current to the second circuit.

A photon detecting component is provided. The photon detecting component includes a first waveguide and a detecting section. The detecting section includes a second waveguide; a detector, optically coupled with the second waveguide, configured to detect one or more photons in the second waveguide; an optical switch configured to provide an optical coupling between the first waveguide and the second waveguide when the detector is operational; and an electrical switch electrically coupled to the detector, wherein the electrical switch is configured to change state in response to the detector detecting one or more photons. The photon detecting component further includes readout circuitry configured to determine a state of the electrical switch of the detecting section.

A method of resolving a number of photons received by a photon detector includes optically coupling a waveguide to a superconducting wire having alternating narrow and wide portions; electrically coupling the superconducting wire to a current source; and electrically coupling an electrical contact in parallel with the superconducting wire. The electrical contact has a resistance less than a resistance of the superconducting wire while at least one narrow portion of the superconducting wire is in a non-superconducting state. The method includes providing to the superconducting wire, from the current source, a current configured to maintain the superconducting wire in a superconducting state in the absence of incident photons; receiving one or more photons via the waveguide; measuring an electrical property of the superconducting wire, proportional to a number of photons incident on the superconducting wire; and determining the number of received photons based on the electrical property.

A device includes at least one array of photoconductors, at least one bias voltage source, and at least one photoconductor readout circuit. Each photoconductor is configured for exhibiting an electrical resistance dependent on an illumination of its light-sensitive region, and at least one photoconductor of the array is designed as characterizing photoconductor. The bias voltage source is configured for applying at least one alternating bias voltage to the characterizing photoconductor or at least one direct current (DC) bias voltage to the characterizing photoconductor. The photoconductor readout circuit is configured for determining of a response voltage of the characterizing photoconductor generated in response to the bias voltage. The response voltage is proportional to a variable characterizing the array of photoconductors. The photoconductor readout circuit configured for determining of the response voltage of the characterizing photoconductor during operation of the array of photoconductors.