Abstract:
An apparatus for controlling an output gain of a silicon photomultiplier device according to the present invention comprises an analog signal processing unit for converting light incident on a silicon photomultiplier device into an analog voltage signal; a digital signal processing unit for receiving the analog voltage signal from the analog signal processing unit and converting the received analog voltage signal into a digital signal; and a control unit for controlling the digital signal processing unit and the silicon photomultiplier device. The control unit receives the digital signal from the digital signal processing unit, and compares the digital signal with a threshold value. When the digital signal exceeds the threshold value, the control unit adjusts the output gain of the silicon photomultiplier device by decreasing a voltage output from the silicon photomultiplier device.
Abstract:
An apparatus for generating a photon with a quantum-entangled-state for a super-resolution optical interferometer is provided to obtain a quantum light source having the high production efficiency and a low noise due to the undesirable photon by applying a heralded photon using a spontaneous parametric down-conversion and a photon detector. An apparatus for generating a photon having a quantum-entangled-state for a super-resolution optical interferometer comprises laser light sources(50,66), photonic crystals(52,68) making two photons from one photon among photons generated in the light sources using a spontaneous parametric down-conversion process, beam dividers(58,62,64) reflecting a part of the photon and transmitting a part of the photon, and a photon detector(70) detecting the photon and generating an electric signal. The photons(1,2) having a quantum-entangled-state are produced and a resolution of the super-resolution optical interferometer is increased.
Abstract:
Plasmonic avalanche photodetection employs an optical antenna and an avalanche photodiode (APD) coupled to the optical antenna. Hot carriers generated by light incident on the optical antenna are received in an avalanche multiplication region of the APD where avalanche multiplication of the hot carriers is provided.
Abstract:
Mapping apparatus (22) includes a transmitter 44, which emits a beam comprising pulses of light, and a scanner (46), which is configured to scan the beam (38), within a predefined scan range, over a scene. A receiver (48) receives the light reflected from the scene and generates an output indicative of a time of flight of the pulses to and from points in the scene. A processor (42) is coupled to control the scanner so as to cause the beam to scan over a selected window (32, 34, 36) within the scan range and to process the output of the receiver so as to generate a 3D map of a part of the scene that is within the selected window.
Abstract:
An accurate and rapid method for characterizing the performance of an APD and setting its operating voltage Vop to an optimal value uses an on-board LED or other pulsed light source to measure APD responses at different operating voltages Vop. An estimated breakdown voltage Vb is determined by comparing the measured responses, and the Vop is adjusted to a new value at a fixed offset from the estimated Vb. The fixed offset is selected according to ambient light conditions, including the presence or absence of light background noise, and whether the sun is partially or fully in the field of view. The method is iterated until convergence, or until a maximum number of iterations is reached. In embodiments, a plurality of APD's having a common Vop can be adjusted, and the Vop is never set below a minimum value VopBW necessary to meet timing requirements for a missile guidance system.
Abstract:
A photon detection system comprising a photon detector configured to detect single photons, a signal divider to divide the output signal of the photon detector into a first part and a second part, where the first part is substantially identical to the second part, delay means for delaying the second part with respect to the first part and a combiner for combining the first and delayed second parts of the signal such that the delayed second part is used to cancel periodic variations in the first part of the output signal.
Abstract:
An optical measurement apparatus (10) comprises a photon detection unit (12) that detects incident photons, a time signal output unit (14) that outputs a time signal, and a storage unit (16) where the time signal outputted from the time signal output unit (14) is stored when photons are detected by the photon detection unit (12). The photon detection unit (12) comprises an HPD (24) having a photo-cathode (24a) and an APD (24b), a TZ amplifier (26), a peak-holding circuit (28), and an A/D converter (30). The time signal output unit (14) comprises a timer (32) and a counter (34). The storage unit (16) comprises a comparator (36) and a memory (38). When photons impinge on the HPD (24), a trigger signal is outputted from the comparator (36), and the photon count outputted from the A/D converter (30) and the time information outputted from the counter (34) are stored in the memory (38).