12 results about "Fluorescence lifetime measurement" patented technology

A time measurement apparatus 10 includes a TAC circuit 12, a measurement gate 11, a control unit 14 for setting a gate dead time, which is a time during which the measurement gate 11 is set to be in the second state, in the measurement gate 11, and the control unit 14 for deriving and outputting time information related to the detection signal based on a measurement signal output from the TAC circuit 12, and the control unit 14 functioning as a setting unit sets a time, which is an integral multiple of a repetition period of fluorescence detected by the detector 4 and is longer than a dead time of the TAC circuit 12 itself, in the measurement gate 11 as a gate dead time.

The invention belongs to the technical field of fluorescence lifetime detection, and particularly relates to a fluorescence lifetime measurement method and system based on low-frame-rate video imaging. The method comprises the following steps: irradiating a to-be-detected sample by adopting an excitation light source, simultaneously collecting a video of a periodic luminescence attenuation process of the to-be-detected sample, and separating the video into a plurality of images with frame number marks; the excitation frequency of the excitation light source and the frame rate of video acquisition meet the following condition: FLED = Fcam + n, and n is a positive integer smaller than Fcam; all the images are converted into gray level images, and the average gray level value of light-emitting areas of the gray level images serves as a fluorescence signal intensity value; storing the fluorescence signal intensity value according to a frame number index, and screening out a signal attenuation sequence from the fluorescence signal intensity value; and fitting the signal attenuation sequence by using a least square method to obtain a fitting curve of the signal intensity value along with the time change, and obtaining the fluorescence lifetime of the sample to be detected from the fitting curve. According to the invention, the detection complexity and cost can be reduced, and the fluorescence lifetime of millisecond or even microsecond level can be measured.

The invention discloses a spectral resolution parallel fluorescence lifetime scanning imaging system, and aims to solve the problems of lack of spectral resolution and slow imaging speed in the conventional fluorescence lifetime scanning imaging technology. The system comprises an exciting light module, a scanning imaging module and a spectral resolution life detection module, the exciting light module generates exciting light with specific repetition frequency; the scanning imaging module is used for realizing relative position mobile scanning of exciting light and a sample and separating to obtain a fluorescence signal; the spectral resolution lifetime detection module adopts a multi-channel photoelectric detector to detect fluorescence of different wavelengths at the same time so as to realize parallel fluorescence lifetime measurement. According to the invention, rapid measurement of spectral resolution fluorescence lifetime imaging is realized, the system has the advantages of high time resolution, high spatial resolution and multifunctional measurement, the system structure is simple, the cost is low, and an ideal tool is provided for imaging research such as biomedicine, chemical analysis and environmental monitoring.

This invention belongs to the technical field of fluorescence lifetime measurement, and discloses a fluorescence lifetime measurement method and system based on time-gated fluorescence imaging. The method includes: acquiring multiple frames of fluorescence images of a sample, wherein the frame rate is greater than the pulse frequency of the pulse beam, and the frame rate and pulse frequency are not integer multiples of each other; the phase difference between two fluorescence images is a delay difference between the sampling delay of the two fluorescence images and their respective reference times; the reference time of each fluorescence image is the on-time of the pulse beam corresponding to its acquisition; calculating the average gray level of the fluorescence images; arranging the average gray levels within multiple pulse beam periods according to the sampling delay to obtain a time-gated sequence of average gray level variation with sampling delay; and obtaining the fluorescence lifetime of the sample by data fitting based on the time-gated sequence. Based on this method, the complexity and cost of detection can be reduced, and the limitations on application scenarios can be lessened.

This fluorescence signal measurement method generates, by using a convolutional neural network (CNN) model on which adversarial training has been performed, a corrected fluorescence signal on the basis of a saturated fluorescence signal in which a saturation phenomenon has occurred. The fluorescence intensity of the saturated fluorescence signal in a first region is a threshold value, and the fluorescence intensity of the corrected fluorescence signal in a second region corresponding to the first region of the saturated fluorescence signal is greater than the threshold value. Fluorescence lifetime information is generated on the basis of the corrected fluorescence signal. A fluorescence lifetime image is generated on the basis of fluorescence lifetime information.

This invention provides a rapid full-spectrum fluorescence lifetime measurement device, aiming to solve the problems of slow measurement speed and difficulty in simultaneously obtaining fluorescence information at multiple wavelengths due to count rate limitations in time-correlated single-photon counting-based fluorescence lifetime measurement methods. The measurement device includes an optical system and a detection circuit system. The optical system is used to split and shape fluorescence signals of different wavelengths, separating wavelengths in one dimension and uniformly distributing light intensity in another. The detection circuit system is used to receive the shaped two-dimensionally distributed fluorescence signal, perform photon counting, obtain the time difference between the excitation light signal and the fluorescence signal, accumulate the number of fluorescence photons in each pixel unit, obtain a fluorescence lifetime decay histogram at different wavelengths, and finally obtain full-spectrum fluorescence lifetime information. This invention utilizes a time-domain-based fluorescence lifetime measurement method, combining fluorescence spot splitting and shaping with a multi-channel detector and signal processing system, to achieve rapid measurement of the full-spectrum fluorescence lifetime of a sample.

The application relates to the technical field of quantum light emitter characterization, and discloses a quantum light emitter dipole structure and orientation characterization system and method.The characterization system comprises a quantum light emitter sample fixing assembly, a fluorescence excitation, fluorescence detection and fluorescence lifetime measurement assembly, a scanning near-field optical probe assembly, a scanning near-field optical probe control assembly and a data processing module.The scanning near-field optical probe assembly performs three-dimensional space scanning around a quantum light emitter to be measured, obtains a Purcell factor distribution, and compares the Purcell factor distribution with a Purcell factor distribution obtained by numerical simulation under any dipole structure and orientation parameter, so as to fit the three-dimensional dipole structure and orientation parameter of the quantum light emitter to be measured.The characterization scheme provided by the application is a near-field characterization scheme based on fluorescence lifetime information, has better robustness and higher resolution compared with a traditional far-field characterization scheme based on fluorescence intensity information, and can more accurately characterize the three-dimensional dipole parameter of the quantum light emitter.

The invention discloses a fluorescence lifetime measuring device and method for a rare earth material. The device comprises an optical flat plate, an adjustable sample table, an optical fiber tail end focuser, an optical fiber tail end recoverer, a laser, a signal generator, an oscilloscope and a photoelectric detector. The device has the advantages that accurate focusing of exciting light and efficient collection of fluorescence can be achieved, and signal loss is reduced; interference of front and back excitation signals is avoided; the whole fluorescence attenuation process can be accurately captured, and the measurement error is small. The structure is designed in a modular mode, and all parts are convenient to install and adjust; the measurement method has clear steps. The output wavelength of the laser can be flexibly replaced according to the characteristic absorption band of a material to be measured, the wavelength response range of the photoelectric detector covers the characteristic fluorescence wavelength of a mainstream rare earth material, and the photoelectric detector can be adapted to measurement of rare earth materials with nanosecond-level to millisecond-level fluorescence lifetime, including various samples such as rare earth simple substances, rare earth oxides, rare earth doped fluorescent powder and the like. The measurement process does not need a complex data analysis algorithm, and is suitable for rapid detection of batch samples.

The invention relates to a fluorescence lifetime measuring device which is characterized in that a modulation instruction is generated by a computer, and a signal generator is driven to generate an alternating-current modulation signal; the first biasing circuit superposes the alternating-current modulation signal onto direct-current biasing current output by the current source to form a composite driving signal to be sent to the excitation light source, and the generated excitation light sequentially passes through the short-pass filter and the dichroic mirror and irradiates a sample to be detected; a fluorescence signal emitted after the sample to be detected is excited sequentially passes through the band-pass filter and the photomultiplier, a direct-current component and an alternating-current component are separated through the second biasing circuit, phase comparison is carried out according to the alternating-current component and an alternating-current modulation signal serving as a reference, phase delay is calculated, and the fluorescence lifetime is deduced. Compared with the prior art, the method has the advantages that the basic brightness of the light source can be maintained, the light intensity modulation is realized, the measurement result is accurate, the anti-interference capability is strong, and the like.

The invention relates to the technical field of environment management, and discloses a radioactive substance leakage rapid detection method and system, and the method comprises the steps: continuously collecting environment parameters, and adjusting the operation state of a first object in combination with the feature parameters of a second object; starting the adjusted first object, exciting a first feature of the second object, and collecting a first feature signal of the second object; transmitting the first characteristic signal of the second object to a third object, and performing signal processing; performing time processing on the first characteristic signal of the second object, and identifying the type of the second object; and according to the first characteristic signal intensity, realizing positioning of the second object, and performing dynamic regulation and control. Through combination of real-time environment monitoring, laser excitation and fluorescence signal processing, accurate detection and positioning of non-radioactive or radioactive substances are realized. The accuracy and sensitivity of signals are improved by adopting a time-resolved fluorescence lifetime measurement technology, and the accuracy of substance positions is further improved by combining a triangulation positioning algorithm.

The invention provides a fluorescence lifetime measuring device based on entangled photon pairs. The fluorescence lifetime measuring device can be applied to the fields of quantum optics and fluorescence spectroscopy. The fluorescence lifetime measuring device based on the entangled photon pair comprises a nonlinear crystal which is used for generating excitation photons and omen photons with a spatial separation angle when being irradiated by continuous laser; the quantum correlation detection module is used for filtering residual laser in the omen photons and reflecting the omen photons to the fluorescence lifetime measurement module; the sample fluorescence excitation module is used for irradiating excitation photons to the surface of the sample and reflecting detection photons generated by excitation of the sample to the fluorescence lifetime measurement module; and the fluorescence lifetime measurement module is used for performing time statistics and data processing according to the electric pulse signal of the detection photon and the trigger signal of the omen photon to obtain the fluorescence lifetime of the sample. The invention also provides a fluorescence lifetime measurement method based on entangled photon pairs.

A fluorophore recognition system performs a further function selected from the group consisting of tracking and imaging. The system includes: a light source that excites a fluorophore with a beam having a distribution with null intensity at a center thereof; a detector that measures photons emitted by the fluorophore; a processing unit that: measures fluorescence lifetime of the fluorophore; compares the lifetime with reference values associated with different fluorophores to identify the target fluorophore; and discriminates against spurious photons on the basis of lifetime. The processing unit also uses the emitted photons to guide performing the further function and minimize additional emissions. Recognition and the further function selected from tracking and imaging can be achieved using a set of fluorescence lifetime measurements in conjunction with discrimination against spurious photons.