782 results about "Photon detector" patented technology

The invention relates to a single-photon transmission device for enabling secure authentication, said device comprising a plurality of single-photon sources, a control device which is configured to actuate each of the single-photon sources separately, and an optical subdevice which is configured to combine single-photon streams of photons emitted by the at least one single-photon source into a QKD coupling beam consisting of a common stream of single photons. The invention also relates to a single-photon receiving device for receiving a QKD coupling beam transmitted from a single-photon transmission device. The invention also relates to a method for generating a common quantum key for a single-photon transmission device and a single-photon receiving device. The invention also relates to an integrated QKD circuit. The invention also relates to a car key comprising a single-photon transmission device and / or a single-photon receiving device. The invention also relates to a car comprising a single-photon transmission device and / or a single-photon receiving device. The invention also relates to the use of a single-photon transmission device and / or a single-photon receiving device for data exchange. The invention also relates to a SPAD diode for a sensor element of a single-photon detector for a single-photon transmission device and / or for a single-photon receiving device.

The invention discloses an OTDR (Optical Time Domain Reflectometer) system, which comprises a signal generator; a circulator; a variable optical attenuator which attenuates the received backward light and outputs an attenuated optical signal; the single-photon detector is used for converting the received attenuated optical signal into an electric signal; the photon counter is used for counting the received electric signals; and a controller that restores the backward light incident on the variable optical attenuator on the basis of the count signal and the attenuation amount of the variable optical attenuator. According to the OTDR system, the variable optical attenuator is used for attenuating the backward light, and the attenuated optical signal enters the single-photon detector, so that the saturation of the single-photon detector is avoided, the anti-saturation capability of the single-photon detector is improved, and the technical problem that the anti-saturation capability of the single-photon detector is poor is solved. Moreover, because the single photon detector is accurate in detection, the counting signal output by the photon counter can be ensured to be accurate, and the controller can also be ensured to accurately restore the back light emitted into the variable optical attenuator.

The invention discloses a password security enhancement method based on secret communication, and particularly relates to the technical field of password security. Transmission and information negotiation of a quantum state are realized by constructing a quantum communication channel and a classical communication channel; after the photons are coded and transmitted, the time delay condition of the photons is analyzed, if the delay is abnormal, a pulse light source simulates photon signals, the trigger probability of the detector is recorded, the time window deviation is judged, delay data and the trigger probability deviation are comprehensively evaluated, the security vulnerability risk caused by non-ideality of the photon detector is quantified, and the security vulnerability risk is evaluated. The method comprises the steps of dividing risks into a high level, a middle level and a low level, implementing corresponding management, dynamically adjusting a compression ratio of privacy amplification by utilizing fuzzy logic according to the middle risk level in combination with a preliminary key bit error rate and a detector risk value, strengthening the anti-eavesdropping capability of a key, and improving the security of a quantum key distribution system through real-time monitoring and dynamic adjustment. The time migration attack is defended, and the long-term security of encrypted communication is guaranteed.

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.

The invention relates to the technical field of optical fiber monitoring and maintenance, and discloses an optical fiber monitoring method, device and equipment, a storage medium and a computer program product, and the method comprises the steps: enabling pulse light of a preset period to be coupled into a to-be-detected low-loss optical fiber based on an optical fiber amplifier and a variable optical attenuator, and generating a backward scattering light signal; converting the backward scattering light signal into an electric pulse signal by using a single-photon detector, and counting the electric pulse signal by using a preset period as a period through a synchronous clock to obtain a counting result; adjusting the power of the variable optical attenuator according to a counting result, and drawing a target signal curve of the to-be-measured low-loss optical fiber based on an adjustment result; and analyzing the target signal curve to obtain a monitoring result of the to-be-measured low-loss optical fiber. The power is dynamically adjusted in different measurement sections, and the multi-section measurement results are superposed, so that the dynamic range of the single-photon optical time domain reflectometer is remarkably expanded, and the loss and dead pixels of the low-loss optical fiber can be reflected more comprehensively and accurately.

The present invention discloses a single-photon detector refrigeration control method and system that is adaptive to temperature and TEC performance changes. The method limits the maximum operating voltage of TEC, monitors the TEC operating voltage and refrigeration temperature in real time, and automatically adjusts the target temperature and APD working bias voltage according to the monitoring results, effectively ensuring that the single-photon detector can still work stably when the working environment temperature is too high or the TEC performance is degraded. At the same time, when the ambient temperature is allowed to return to the normal temperature range, the TEC's refrigeration target temperature can be restored to the initial refrigeration target temperature and the APD's working bias voltage can be adjusted synchronously, so that the performance indicators of the single-photon detector, such as the detection efficiency, dark count rate, and after-pulse probability, will be synchronously restored to normal. In this way, the service life of TEC and single-photon detector equipment can be effectively improved, and the environmental adaptability of the single-photon detector can be improved.

The invention discloses a multi-dimensional random number generator and a multi-dimensional random number generation method. The multi-dimensional random number generator comprises a single photon source, a polarization beam splitter, a 50: 50 beam splitter, a first single photon detector, a second single photon detector, a third single photon detector, a photon counter and a control processing module. Extraction and conversion of polarization correlation randomness, path correlation randomness and time correlation randomness are completed in the same system, the quantum random number sequence based on multiple principles is generated, the multi-dimensional quantum random number sequence is generated through a characteristic joint coding method, the randomness is higher, and the quantum random number sequence is more uniform. Extra chip hardware is not needed to provide computing power and post-processing operation, and the process is simpler, more efficient and more stable. In addition, the multi-dimensional random number generator provided by the invention is simpler and more compact in structure, and the entropy source utilization efficiency and the device damage resistance of the quantum random number generator are improved.

The invention discloses an amorphous tungsten superconducting nanowire single-photon detector, which comprises a photosensitive component, and is characterized in that the photosensitive component is an amorphous tungsten superconducting nanowire; the amorphous tungsten superconducting nanowire is prepared by the following steps: (1) growing an amorphous tungsten film on a substrate; and (2) etching the amorphous tungsten film into a roundabout nanowire structure by using electron beam exposure and reactive ion etching methods to obtain the amorphous tungsten superconducting nanowire. According to the invention, the tungsten nanowire with good stability is used as the main body material of the SNSPD, so that the robustness of the SNSPD preparation process is improved, and the service life of the SNSPD device in practical application is prolonged.

The invention provides a scanning-type single-photon laser radar system based on phase regulation, and the system employs a reflection-type liquid crystal spatial light modulator to carry out the phase regulation of a laser beam, and achieves the long-distance fixed-point focusing through the modulation of laser wavefront. And echo signal detection is carried out by using a single-photon detector. Before the reflection type liquid crystal spatial light modulator is used for carrying out phase regulation and control on a laser beam, the laser beam is divided into reference light and detection light through the light splitting module, and then the divergence angle of the laser beam is reduced through the beam expanding module; after phase regulation and control, scanning of a laser beam in a target area is controlled through a reflector and a two-dimensional scanning galvanometer.

The invention discloses a single-photon laser radar imaging system and method for underwater target detection, and belongs to the technical field of detection imaging. The imaging system comprises an optical system and a control system, and the optical system comprises a transmitting unit, a receiving unit, a single-photon detector and a scanning unit. An optical path of the optical system adopts a transmitting-receiving combined optical path structure, the transmitting unit transmits an optical signal, the scanning unit receives the transmitted optical signal and a control signal and reflects an echo optical signal, the echo optical signal generated by the optical signal transmitted by the transmitting unit is received by the receiving unit, the echo optical signal is converged to the single-photon detector, and the single-photon detector is used for detecting the single-photon. The single-photon detector performs photoelectric conversion; the control system comprises an FPGA control board, and the FPGA control board is connected with a communication module, a gating signal module and a scanning signal module. The system is compact in structure and reasonable in design, detection of weak optical signals can be realized by using a reasonable optical path structure and the single-photon detector, and the farthest detection distance is increased.

The invention provides a single photon pulse laser radar target detection method and system. The method comprises the following steps: modulating pulse emission time delay by adopting a pseudo-random number function to obtain a pulse laser emission time sequence; a precise time-to-digital converter is adopted to collect output signals of the single-photon detector, the arrival time of photons is recorded, and an echo photon time sequence is obtained; the method comprises the following steps: intercepting echo photon time subsequences in a pulse laser emission time sequence according to a fixed length sequence, delaying the echo photon time subsequences in combination with an echo photon time sequence delay amount to obtain a delay subsequence, and carrying out matching counting on the delay subsequence and the echo photon time sequence to obtain a matching counting number; continuously adjusting delay to obtain a matching function; and performing threshold detection on the matching function, and calculating a target distance by taking an echo photon time subsequence delay amount corresponding to the threshold detection as pulse round-trip flight time. According to the invention, the problem of fixed pulse repetition frequency ranging ambiguity is solved.

Optical sensing apparatus includes a transmitter, which is configured to transmit outgoing frequency-modulated (FM) coherent optical radiation toward a target scene. A receiver includes an array of single-photon detectors, which are configured to output electrical pulses in response to photons that are incident on the detectors. Optics image the target scene onto the array while diverting a part of the outgoing FM coherent optical radiation to form a local beam, which mixes with incoming optical radiation from the target scene. Processing circuitry is configured to compute counts of the electrical pulses output as a function of time by the single-photon detectors in response to the mixed optical radiation, to extract beat frequencies from the computed counts, and to measure ranges of points in the target scene responsively to the beat frequencies.

The invention provides a single-photon avalanche diode and a single-photon detector, and relates to the technical field of semiconductor photoelectric detection, and the single-photon avalanche diode comprises a plurality of avalanche diode units. The avalanche diode units are sequentially stacked in the propagation direction of incident light to be detected. Each avalanche diode unit is provided with an electric field control module which is used for independently adjusting the bias electric field of each avalanche diode unit. In the propagation direction of the incident light, the avalanche diode unit of the next stage is used for absorbing the remaining photons which are not absorbed by the avalanche diode unit of the previous stage and generating carriers, so that avalanche current is formed. The light absorption wavelength ranges of adjacent avalanche diode units are at least partially overlapped. The single-photon avalanche diode solves the problem that the existing single-photon avalanche diode cannot balance high detection efficiency and low dark current, and achieves the purpose of improving the detection efficiency of a single-photon detector on the premise of not increasing the dark current.

The invention relates to a quantum computer, which comprises a sample (21) with paramagnetic centres, preferably in the form of NV centres (22), and a pumping radiation source (1). The pumping radiation source (1) irradiates, by means of an optical system, the paramagnetic centres and / or NV centres (22) with pumping radiation (54) of a pumping radiation wavelength (λpmp) over a first optical partial path. The optical system detects the fluorescent radiation (33) of the paramagnetic centres (22) and guides the fluorescent radiation (33) to a photodetector (50) and / or a single-photon detector (50) over a second optical partial path. The first optical partial path differs from the second optical partial path at least in some portions. The photodetector (50) and / or the single-photon detector (50) convert the fluorescent signal of the fluorescent radiation (33) of the paramagnetic centres (22) into at least one measurement signal and / or at least one measurement value. The quantum computer uses this at least one measurement signal and / or this at least one measurement value to carry out a quantum operation. The device is characterised in that the quantum computer has an optical spatial filter in the second optical partial path.

The invention relates to an optical time domain reflectometer and a control method of the optical time domain reflectometer, and relates to the technical field of photoelectricity. The optical time domain reflectometer OTDR comprises a single photon detector, and the OTDR is used for being connected with an optical fiber to be measured; the OTDR is further used for sending a plurality of detection signals to the optical fiber to be detected in sequence and receiving a plurality of detection echo signals from the optical fiber to be detected in sequence, and the detection echo signals are used for indicating the transmission state of the same section of transmission area in the optical fiber to be detected; performing amplitude reduction processing on each detection echo signal at a certain time interval to obtain a processed detection echo signal; the positions, corresponding to the same section of transmission area, of the signal sections subjected to amplitude reduction processing in the different processed detection echo signals are not completely the same; each processed detection echo signal is subjected to photoelectric conversion based on the single-photon detector to obtain a first electric signal, a first OTDR oscillogram is output based on the multiple first electric signals, and the first OTDR oscillogram is used for indicating the transmission state of the same section of transmission area. Therefore, the problem of OTDR curve distortion can be solved.

Disclosed is a single photon detector comprising a semiconductor substrate and a 2D material layer provided adjacent to the semiconductor substrate, the semiconductor substrate includes a first well having a first conductivity type, a heavily doped region having a second conductivity type different from the first conductivity type, and a depletion region provided between the first well and the heavily doped region.

The present invention belongs to the field of quantum navigation and positioning technology, and discloses an inter-satellite ranging system, method, device and data processing terminal. The inter-satellite ranging system includes: a photon transceiver unit, which is used to generate entangled photon pairs, transmit signal photons to the satellite to be measured and the internal optical path, and receive signal photons reflected by the satellite to be measured and the internal optical path; a coincidence counting unit, which is used to associate the received signal photons with the idle photons to obtain their second-order correlation curves; a distance measurement unit, which is used to perform DFT phase difference weighted processing on two second-order correlation curves generated by the optical path difference inside and outside the system to obtain the actual optical path difference from the satellite to be measured to the system. The present invention uses a photon matching method to filter out the cosmic space stray light entering the photon detector to a large extent, thereby improving the signal-to-noise ratio. The present invention adopts an improved coincidence counting algorithm, and the calculation rate is greatly improved compared with the traditional coincidence counting algorithm.

The invention relates to the field of computational imaging, in particular to a computational imaging method of a crossed strip-shaped anode single-photon detector, which comprises the following steps of: screening effective data through full-view-field illumination, and calculating an average output signal amplitude of each anode strip and a total average output signal amplitude of all anode strips to obtain a correction factor; the method comprises the following steps of: correcting an original output signal of each anode strip by adopting a correction factor during target imaging, performing effective signal data screening on the corrected original output signal, substituting effective signal data into a Gaussian algorithm to calculate an incidence position coordinate, mapping the incidence position coordinate to a mapping matrix, and stretching the incidence position coordinate to a 256 gray level for display. According to the calculation imaging method provided by the invention, the fixed mode noise can be suppressed, the imaging resolution is improved, and the image distortion is reduced.

The invention discloses a full waveform and single photon counting mixed distance measurement system and method, and the method employs a high-speed ADC to directly collect analog pulse signals generated by a single photon detector, obtains the full waveform, achieves the waveform recognition and cutting through the analysis of a first-order local extreme point, and employs a single photon waveform high-speed fitting algorithm to achieve the measurement of the full waveform and single photon counting mixed distance. The peak moment of the analog pulse signal is obtained with high precision, distance walking errors and time interval measurement errors are effectively suppressed, and the improvement of the single-photon distance measurement precision is realized by further combining with a time-dependent single-photon coincidence counting method.

The invention relates to the field of LED display screen defect detection, in particular to an LED display screen defect rapid detection method. The method specifically comprises the steps that polarization entangled photon pairs are generated through a first detection assembly, the photon pair coincidence counting rate is measured through an HOM interferometer and a single-photon detector in a second detection assembly, and a photon pair anomaly distribution diagram is generated; establishing a correlation model of the photon pair coincidence counting rate and the electronic state density, and analyzing internal defects of the display screen; an integrated high-speed CMOS camera and a multiband LED annular light source are adopted to collect four-channel image data, and features are extracted to generate an image data abnormal probability graph; and finally, integrating a quantum optical measurement result and an image analysis result through coordinate mapping, judging a final defect area and type based on a decision tree rule, and covering various defect types such as material internal defects, surface reflection abnormity and color unevenness. According to the method, the efficiency and the accuracy of LED display screen defect detection are remarkably improved.

Systems and methods include acquisition of an anatomical image of an object, acquisition of molecular imaging data of the object at the plurality of photon detectors, reconstruction of a functional image based on the molecular imaging data, input of the anatomical image and the functional image to a trained neural network to generate a second functional image, and presentation of the second functional image.

The invention provides an entangled light quantum three-dimensional color imaging method based on photon flight time. The method comprises the following steps: firstly, irradiating pump light to a periodically poled potassium titanyl phosphate crystal, and generating a spontaneous parametric down-conversion process to obtain entangled photon pairs; then, photon arrival time pulse sequences of the signal light path and the reference light path are collected through a single photon detector; secondly, calculating the flight time difference of the signal light and the reference light at each pixel point through coincidence measurement to obtain the distance between the corresponding position and the light source; thirdly, estimating the target reflectivity according to the probability density function of coincidence counting of the two paths of photons; and finally, realizing quantum three-dimensional color imaging according to the distance information of the corresponding position of each pixel point and the target reflectivity.

The utility model discloses a single-photon detector, which comprises a controller, a bias voltage generating circuit, a refrigeration temperature control circuit, a gating voltage generating circuit, an avalanche signal extraction circuit and an avalanche photodiode (APD) refrigeration box, and is characterized in that one end of the bias voltage generating circuit, one end of the gating voltage generating circuit and one end of the avalanche signal extraction circuit are connected to the controller; one end of the refrigeration temperature control circuit is connected to a TEC of the APD refrigeration box, the other end of the refrigeration temperature control circuit is connected to the controller, the other end of the avalanche signal extraction circuit is connected to an anode of an APD in the APD refrigeration box through an alternating current coupling capacitor C2, the anode of the APD is grounded through a sampling resistor R2, the other end of the bias voltage generation circuit is connected to a cathode of the APD through a resistor R1, and the APD refrigeration box is connected to the APD refrigeration box. And the other end of the gating voltage generation circuit is connected to the cathode of the APD through an alternating current coupling capacitor C1. According to the technical scheme of the utility model, the passive quenching of the free operation working mode is realized, the dead time processing circuit is simplified, and the noise level of the detector is reduced.

The invention relates to the technical field of quantum measurement, and provides a high-precision quantum distance measuring device and method based on a frequency entangled state, and the device comprises an entangled photon source, a polarization beam splitter, a single-mode optical fiber coupler group, an optical fiber circulator, and an optical receiving and transmitting antenna. The entangled photon source comprises a pump light source, a first lens, a nonlinear optical crystal, a temperature control furnace, a temperature control module, a second lens, a dichroscope and a long pass filter; a third port of the polarization beam splitter is connected with a reflector, the reflector is connected with a second single-mode optical fiber coupler, and the second single-mode optical fiber coupler is connected with a second single-photon detector; a second port of the polarization beam splitter is connected with a first single-mode optical fiber coupler, the first single-mode optical fiber coupler is connected with an optical fiber circulator, one end of the optical fiber circulator is connected with an optical transceiving antenna, and the other end of the optical fiber circulator is connected with a first single photon detector; the method has the advantages of wide range and high-precision distance measurement, and can better complete distance measurement.

The invention discloses a single-photon three-dimensional imaging system based on double-optical-wedge scanning and a registration method. According to the single-photon three-dimensional imaging system based on double-optical-wedge scanning, multi-beam emission illumination based on Dammann gratings is adopted, so that the energy utilization efficiency can be effectively improved, and the detection distance is increased; by adopting the area array single-photon detector, high-sensitivity detection of extremely weak long-distance target reflected light signals can be realized; an imaging view field can be expanded under the condition that image rotation is not introduced by adopting a double-optical-wedge scanning mode; internal reflection can be effectively inhibited and a close-range detection blind area can be eliminated by adopting sub-aperture common-path coupling; a prior-based rapid reconstruction algorithm is adopted, so that the three-dimensional image reconstruction speed of double-optical-wedge scanning can be effectively improved; by adopting an off-axis focal plane method, high-efficiency coupling registration of emitting laser beams and receiving the field of view of the area array detector can be realized.

The invention discloses a signal synchronization method and system based on a free space quantum key distribution system, and belongs to the technical field of key transmission. A high-power synchronous laser is adopted as a synchronous light source, a preset frame identification head is adopted to modulate a synchronous light signal, the modulated synchronous light signal serves as reference light and is sent to a receiving end, then synchronous coding is conducted on the synchronous signal received by a synchronous detector of the receiving end, and position information of the synchronous signal is generated and sent to a single photon detector of the receiving end; and performing sequence correspondence on the quantum signal received by the single-photon detector at the receiving end and the synchronizing signal according to the position information to finish signal synchronization. Frame synchronization is achieved through the synchronous laser, bit synchronization is achieved through synchronous coding and sequence correspondence, interference of an atmospheric channel can be effectively resisted, and the bit error rate of the system is reduced.

The invention discloses an infrared dual-band single-photon laser radar imaging system, and belongs to the field of laser radar detection. The system comprises an infrared dual-band light source, a beam splitter, a first delay line, a light splitting module, a transceiver module, a frequency up-conversion module, a photoelectric detector, a single-photon detector, a signal acquisition module and a signal processing module. The infrared dual-band light source generates near-infrared and intermediate-infrared pulse laser; near-infrared laser is used for near-infrared detection, frequency up-conversion pumping and initial signals after passing through a beam splitter, intermediate-infrared laser is used for intermediate-infrared detection, intermediate-infrared detection signal echoes are subjected to time domain gating and frequency up-conversion by near-infrared pumping signals and then injected into a single-photon detector together with near-infrared detection signal echoes through time division multiplexing, and the intermediate-infrared detection signal echoes and the near-infrared detection signal echoes are subjected to frequency up-conversion. And detection imaging is realized through signal acquisition and processing. According to the invention, the weak target detection imaging capability of the single-photon laser radar in environments of gas, strong background noise and the like can be improved, and the multi-band sensing capability of the radar on target characteristics is improved.

A method of making a single-photon detector includes growing an epitaxial multi-layer structure that includes a buffer layer, an absorption layer, a transition layer, a field control charge layer, a multiplication layer, an inversion layer, a migration layer, a window layer, and an Ohmic contact layer sequentially on a substrate. A curved diffusion region is formed in the window layer and the Ohmic contact layer via a diffusion process. A mesa structure is formed by etching the epitaxial multi-layer. A light input window is formed on the substrate. A p-type electrode is formed on the Ohmic contact layer, and an n-type electrode is formed on the substrate. The inversion layer provides supplementary regulation of an electric field distribution that is regulated by the field control charge layer. A single-photon detector made from the method, and a single-photon detector array made with a multitude of the single-photon detectors are also provided.

The invention discloses a single-photon non-vision-field target tracking system based on an unmanned aerial vehicle platform, which belongs to the field of non-vision-field imaging and is characterized in that a laser is connected with a scanning galvanometer assembly through a first nanosecond optical path switch and an optical fiber circulator to form an emission optical path for emitting laser pulses to relay reflecting surfaces corresponding to four predetermined positioning points; the scanning galvanometer assembly is connected with the photon detector through the collimating optical fiber, the optical fiber circulator and the second nanosecond optical path switch to form a receiving optical path capable of receiving echo photons; the main control module is electrically connected with the laser, the first nanosecond light path switch, the second nanosecond light path switch, the scanning galvanometer assembly, the photon detector, the time-to-digital converter and the high-frequency inertial measurement unit respectively, and can control each component to perform laser ranging, double-window gating, single-photon detection, inertial measurement unit sampling and timing according to a unified time sequence; and the three-dimensional coordinates of the current non-vision target are calculated by using the distance measurement data through an ellipsoid intersection solution method, so that non-vision target tracking is realized.

The invention relates to the technical field of light quantum metering, in particular to a multifunctional standard single photon source generation and calibration device and a use method, and the device comprises a pumping laser light source, a nonlinear crystal, a signal optical filter, a beam splitter, a temperature control module, an idler frequency optical filter, a control module, a single photon detector group, a beam splitter, a multi-channel coincidence counter, and an optical switch. The pumping laser light source pumps the nonlinear crystal to generate two paths of single photon output of signal light and idler frequency light, the two paths of single photon output are filtered by the filter and then divided into multiple paths by the beam splitter, and standard single photons are directly output or the paths of the signal light or the idler frequency light are controlled by the optical switch to enter the single photon detector group for detection. External input single photons are controlled by the optical switch to enter the single-photon detector group for detection, and a count value of the single-photon detector group is accessed to the multichannel coincidence counter to record data. A pump light stable power system and a multi-path beam splitting coincidence counting system are introduced into a light path, so that standard single photon output with known brightness and g (2) (0) value can be realized.