17 results about "Optical photon" patented technology

The present invention relates to a photon counting detector and method. The detector (20) comprises a scintillator (21) configured to convert incident gamma radiation into optical photons, a pixelated photodetector (22) configured to detect the flux of optical photons, and circuitry (23). The circuitry (23) is configured to iteratively determine, per photodetector pixel, a photon count by accumulating the number of optical photons detected by the respective photodetector pixel during an integration time, assign the photon count, per photodetector pixel, to one of multiple energy bins by use of energy thresholds separating the multiple energy bins, and dynamically adapt, per photodetector pixel or group of photodetector pixels, the energy thresholds for use in a subsequent iteration based on information on the estimated photon count of said photodetector pixel or group of photodetector pixels in the subsequent iteration.

A microwave-to-optical photon transducer is provided for generating coupling between a microwave signal (Sin2) and an optical signal (Spi_in1, Spi_out1). The transducer comprises: a first input port; a second input port; a first output port for outputting the optical signal (Spi_out1) and one or more optical sideband signals (Sout1, Sout11, Sout12); a first waveguide disposed between the first input port and the first output port to allow the optical signal (Spi_in1) and the one or more optical sideband signals (Sout1, Sout11, Sout12) to propagate in the first waveguide; a second waveguide connected to the second input port, and extending in the transducer adjacent to the first waveguide to allow the microwave signal (Sin2) to propagate in the second waveguide; a phase-matching arrangement to cause at least the optical signal (Spi_in1) and the microwave signal (Sin2) to be phase-matched or quasi-phase-matched.

A method of improving a generated image obtained from a gamma camera for medical imaging, the image being improved by excluding the contribution of low-energy and scattered gamma rays to the generated image, the method comprising the steps of: detecting gamma ray photons by the gamma camera; converting the detected gamma ray photons into one or more optical photons; detecting the resulting optical photons on the photosensitive surface; processing the detected optical photons into a primary data array comprising pixels, where the pixels map the detection of the optical photons on the photosensitive surface, where the filling pixels correspond to the detection of the optical photons on the photosensitive surface; identifying a cluster of padding pixels in the primary data array; determining a density of fill pixels in the identified clusters; classifying the clusters into high-density clusters (clusters with high-density filled pixels) and low-density clusters (clusters with low-density filled pixels); the contributions of low-density clusters to the generated image are excluded, the low-density clusters corresponding to low-energy and scattered gamma rays.

The present invention relates to a photon counting detector comprising a scintillator (10, 20) configured to convert incident gamma radiation into optical photons; a pixelated photodetector (11, 22) configured to detect the flux of optical photons wherein the pixelated photodetector (22) is a silicon photomultiplier, SiPM, detector, wherein each photodetector pixel comprises an array of silicon avalanche photo diodes, SPADs; and circuitry (80, 90) configured to heat SPADs by applying, if dark count rate of a SPAD exceeded a dark count rate threshold, an elevated reverse bias voltage to the SPAD to force the SPAD into breakdown with current flowing through the SPAD for the time of a heating period to locally increase the temperature of the SPAD, and controlling the length of the heating period.

A method of improving a generated image obtained from a gamma camera used in medical imaging, the image improved by excluding low energy and scattered gamma rays from contributing to the generated image, the method comprising the steps of: • the gamma camera detecting gamma ray photons; • converting the detected gamma ray photons into one or more optical photons; • detecting the resultant optical photons on a photoactive surface; • processing the detected optical photons into a primary data array comprising pixels, wherein the pixels map the detection of the optical photons on the photoactive surface, wherein populated pixels correspond to the detection of the optical photons on the photoactive surface; • identifying clusters of populated pixels in the primary data array; • determining the density of the populated pixels in the identified clusters; • categorizing the clusters into high density clusters (clusters having a high density of populated pixels) and into low density clusters (clusters having a low density of populated pixels); • excluding the low density clusters from contributing to the generated image, these low density clusters corresponding to low energy and scattered gamma rays.

Provided herein are systems and methods that combine the use of first and second optical transformations (e.g., implemented using optical photon reassignment (OPRA)) with time delay and integration (TDI) imaging and external illumination to provide high throughput imaging while maintaining a high signal to noise ratio and providing enhanced image resolution.

The present invention relates to a photon counting detector and method. The detector comprises a scintillator (21) configured to convert incident gamma radiation into optical photons; a pixelated photodetector (20, 30) configured to detect the flux of optical photons wherein the pixelated photodetector is a silicon photomultiplier, SiPM, detector, wherein each photodetector pixel comprises an array of silicon avalanche photo diodes, SPADs; and circuitry (23, 90) configured to carry out, per photodetector pixel, the steps of controlling a stop timing at which one or more functions of the photodetector pixel are stopped; determining a first photon count by accumulating the number of optical photons detected by the SPADs of the respective photodetector pixel from the start of an integration period up to the stop timing; and estimating a second photon count based on the first photon count and the stop timing, the second photon count representing an estimate of the photon count for the total integration period.

Microwave-optical interface apparatus and methods are disclosed. In one example embodiment, a microwave-optical interface apparatus comprises: a microwave cavity operable to, at least, host at least one microwave signal photon; and an optical cavity comprising a plurality of embedded defects, the optical cavity operable to, at least, host at least one optical signal photon and at least one optical pump electric field, the optical cavity positioned relative to the microwave cavity to cause, using the plurality of embedded defects and induced by the at least one optical pump electric field, three-wave mixing magneto-optic transduction between the at least one microwave signal photon, the at least one optical signal photon and the at least one optical pump electric field within the optical cavity; wherein the at least one optical signal photon and the at least one optical pump electric field are evanescently confined within the optical cavity in at least two dimensions.

The invention provides a method and a system for enhancing radiation imaging resolution. The device comprises a water tank, an optical photon high-sensitivity CCD (Charge Coupled Device) detector, a 360-degree detector rotating system and a computer processing unit, wherein the water tank is used for packaging a Cerenkov light emitting solution. According to the method, light intensity data of fluorescence emitted by Cerenkov light excitation quantum dots generated by MV-level rays in a water tank is acquired from multiple angles, light intensity distribution is obtained through three-dimensional reconstruction theory and technology reconstruction of limited optical detection information, and three-dimensional dose distribution of beams is finally obtained according to a quantitative relation between light intensity and dose deposition. The radiation therapy dose monitoring system provided by the invention can obtain three-dimensional dose distribution, is good in real-time linearity and simple in measurement, and can effectively ensure the curative effect of radiation therapy and guarantee the radiation safety of a patient.

The present invention provides methods and apparatuses for radiographic imaging of ionizing radiation, including X-ray / gamma ray, neutron or other particle imaging, where a scintillator is used to convert high-energy particles or photons to optical photons.

Microwave-optical interface apparatus and methods are disclosed. In one example embodiment, a microwave-optical interface apparatus comprises: a microwave cavity operable to, at least, host at least one microwave signal photon; and an optical cavity comprising a plurality of embedded defects, the optical cavity operable to, at least, host at least one optical signal photon and at least one optical pump electric field, the optical cavity positioned relative to the microwave cavity to cause, using the plurality of embedded defects and induced by the at least one optical pump electric field, three-wave mixing magneto-optic transduction between the at least one microwave signal photon, the at least one optical signal photon and the at least one optical pump electric field within the optical cavity; wherein the at least one optical signal photon and the at least one optical pump electric field are evanescently confined within the optical cavity in at least two dimensions.

A microwave-optical interface apparatus and method are disclosed. In one example embodiment, a microwave-optical interface device comprises: a microwave cavity operable to receive at least one microwave signal photon; and an optical cavity comprising a plurality of embedded defects, the optical cavity operable to receive at least at least one optical signal photon and at least one optical pump electric field, the optical cavity positioned relative to the microwave cavity, to cause a three-wave mixing magneto-optical transduction between the at least one microwave signal photon, the at least one optical signal photon, and the at least one optical pump electric field within the optical cavity using the plurality of embedded defects and induced by the at least one optical pump electric field; wherein the at least one optical signal photon and the at least one optical pump electric field are evanescently confined within the optical cavity in at least two dimensions.

The present invention provides a multi-channel filter based on period multiplication photonic crystal, belonging to the field of optical technology. The arrangement rule of the period multiplication sequence in the multi-channel filter is: S0 = H, S1 = HL, S2 = HLHH, ..., S N =S N‑1 S N‑2 S N‑2 , ..., where N is the number of the periodic doubling sequence, S N represents the Nth term of the periodic multiplication sequence; wherein H is the first dielectric layer, L is the second dielectric layer, the first dielectric layer and the second dielectric layer are two uniform dielectrics with different refractive indices; the thickness of the first dielectric layer and the second dielectric layer is 1 / 4 of the optical wavelength corresponding to their respective refractive indices. The present invention has optical fractal forms of multi-wavelength resonance, corresponding to a series of transmission modes, and these optical fractal forms can be used in multi-channel photon filters.

Quantum entanglement may be distributed at a high rate over an optical link by sequential emission of spin-entangled optical photon states from different matter based quantum systems into the optical link and execution of a heralded entanglement protocol using the emitted photon states. The quantum systems can be provided by luminescent centers such as T centres, for example. Quantum states of the quantum systems may be transferred to other quantum systems after emission of the photon states. Entanglement swapping may be performed to extend the entanglement to be between quantum systems. The technology has example application in cases where optical fibre links are shared between many nodes and / or where it is desired to extend entanglement to an orbiting satellite, and is particularly useful when optical links are not simultaneously available.

The invention relates to a photon counting detector and a method. The detector comprises: a scintillator (21) configured to convert incident gamma radiation into optical photons; a pixelated photodetector (20, 30) configured to detect a flux of optical photons, where the pixelated photodetector is a silicon photomultiplier, SiPM, detector, where each photodetector pixel comprises an array of silicon avalanche photodiodes, SPAD; and circuitry (23, 90) configured to perform, for each photodetector pixel: control a stop timing to stop one or more functions of the photodetector pixel; determining a first photon count by accumulating the number of optical photons detected by the SPAD of a corresponding photodetector pixel from the start of an integration period up to the stop timing; and estimating a second photon count based on the first photon count and the stop timing, the second photon count representing an estimation of the photon count for a total integration period.

The present invention relates to a photon counting detector and method. The detector (2) comprises a scintillator (10) configured to convert incident gamma radiation into optical photons, a pixelated photodetector (11) configured to detect the flux of optical photons, and circuitry (12). The circuitry is configured to determine, per photodetector pixel, a photon count by accumulating the number of optical photons detected by the respective photodetector pixel during an integration time period, compare, per photodetector pixel or group of photodetector pixels, a single photon count or multiple photon counts to a counting threshold, detect an event if, per photodetector pixel or group of photodetector pixels, the one or more photon counts exceed the counting threshold, and temporarily adapt the counting threshold for use in the comparison in one or more subsequent integration time periods based on the energy of the detected event.