32results about How to "High wavelength accuracy" patented technology

A tunable laser system utilizes a frequency shift compensated acousto-optic tunable filter. The wavelength accuracy and stability is achieved by a wavelength locker utilizing two separate intracavity light beams without the need to use beam splitters to significantly reduce the space typically needed by a conventional wavelength locker, and provide more stable operation and easy assembly. The acoustic optical tunable filter includes an acousto-optical crystal with a transducer coupled to the crystal to generate acoustic waves, and an optical mirror to reflect the diffracted light beam back to the acousto-optical medium again such that the frequency shift by two diffractions is compensated. By using different laser gain mediums, acoustic wave driving frequencies and acousto-optical crystals, this invention can be used to make tunable lasers in wide range of optical wavelengths for many different applications.

Provided is a process for producing colloidal crystals from which a large single crystal reduced in lattice defects and unevenness can be easily produced at low cost without fail. The process for colloidal crystal production comprises: preparing a colloidal polycrystal dispersion in which colloidal crystals precipitate at a given temperature (preparation step); introducing into a vessel The colloidal polycrystal dispersion in the state of containing fine colloidal polycrystals precipitated (introduction step); and melting the colloidal polycrystals and then recrystallizing the molten polycrystals (recrystallization step). The crystals thus obtained have fewer lattice defects and less unevenness than the original polycrystals.

The invention relates to an ultra-large FOV (Field Of View) static polarized Fourier transform imaging spectrometer comprising a front telescope system, a polarizer, an FOV compensation-type polarized beam splitter, a polarization analyzer, an imaging lens group and a detector which are coaxially and sequentially arranged, wherein the detector is connected with a signal collecting and processing system. The invention introduces two Savart polarizers which respectively have positive and negative interference fringe distortion to form the polarized beam splitter so that the positive interference fringe distortion and the negative interference fringe distortion can mutually counteract so as to enlarge the FOV angle. The invention has the advantages of small size, light weight, simple and compact structure, no motion part, large FOV, great luminous flux, high detection sensitivity, noise-signal ratio and wavelength accuracy and wide spectral detection range.

An optical coherence tomographic imaging apparatus for splitting light emitted from a light source into reference light and signal light and creating an optical coherence tomographic image and tomographic spectral information in a predetermined spectral analyzing portion in the optical coherence tomographic image based on optical interference signal information of the reference light and the signal light which are incident on an inspection target and reflected on respective layers, the optical coherence tomographic imaging apparatus including a spectral information processing unit for performing a spectral information calculation using an optical interference signal of a deeper region and creating the tomographic spectral information of the spectral analyzing portion. With this arrangement, spectral information corresponding to the optical coherence tomographic image can be output with high wavelength accuracy.

The invention provides a fiber bragg grating interrogator based on a digitization tunable light source. The fiber bragg grating interrogator based on the digitization tunable light source is characterized by comprising the digitization tunable light source, a coupler of a circulator, a photovoltaic conversion module, a data acquisition unit and a calculation and control unit, wherein wavelength and power of the digitization tunable light source are capable of being arbitrarily set, and the data acquisition unit is provided with synchronizing signals. Light emitted by the digitization tunable light source passes through the coupler or the circulator, enters a testing optical fiber, and is reflected by a fiber bragg grating on the testing optical fiber, and the light which carries tested information reversely passes through the coupler of the circulator and lights onto the photovoltaic conversion module. Signals of the light are collected by the synchronous data acquisition unit, and are sent into the calculation and control unit, reflected wavelength of the fiber bragg grating is calculated according to reflectivity of different wavelength, and information of temperature and strain of the fiber bragg grating to be tested is obtained. The fiber bragg grating interrogator based on the digitization tunable light source has the advantage of being capable of eliminating the synchronization problem of a traditional scanning type light resource caused by different distance of the fiber bragg grating.

The invention belongs to the field of spectrum instruments, and provides a novel Full-fiber Fourier transform spectrometer, which improves the precision and the reliability of the FFTS instrument, eliminates noise and artifacts, and has the characteristics of miniaturization, portability and the like. The technical solution adopted by the invention is a full-fiber Fourier transform spectrometer based on the PZT phase modulation real-time compensation, and the structure is as follows : the sensing arms of the two optical fiber interferometers are wound on the same optical fiber phase modulatorPZT, so that the two optical fiber interferometers are fully synchronized and consistent; the test light enters one input end of the broadband coupler WIC1 through a coupling lens, and is divided intotwo bundles of 50:50 through the coupler WIC1, one bundle of fibers wound by the piezoelectric ceramic phase modulator in parallel, and the other bundle passing through the arm length matching fiber., respectively, enters the input end of the wideband coupler WIC2, and forms interference fringes at its output end after passing through the wideband coupler WIC2. The full-fiber Fourier transform spectrometer based on PZT phase modulation real-time compensation is mainly applied to the field of spectrum detection.

The invention discloses a transmittance spectrum measurement device and method for an ultra-narrow band filter. The device comprises a light source system, a convergent mirror, a collimating mirror, a sample holder, a light signal receiving system, a data analyzing and processing system and the like. The device is characterized in that the light source system adopts an LED light source with stable high output power, continuous emission wavelength and emission spectrum bandwidth larger than 30 nm; a laser wavelength meter with high wavelength accuracy and high spectral resolution is used as a light signal receiver, a computer is used for data analyzing and processing, and finally a transmittance spectrum curve of the ultra-narrow band filter is obtained. According to the device, the structure is simple and practical, the constructing cost is low, the measurement method is simple, convenient, reliable and rapid, compared with a conventional spectrophotometer, both the wavelength accuracy and the spectral resolution of the device are higher, the actual spectrum performance of the ultra-narrow band filter can be accurately reflected, and the device and the method are particularly suitable for spectral bandwidth measurement and central wavelength locating of the ultra-narrow band filter with the bandwidth in the range of 0.1-1 nm.

This invention discloses a fluorescence detector, which comprises fluorescence triggering light path and fluorescence receiving light path. The said fluorescence triggering light path is composed with layer source, interference filter and sample pool. The fluorescence receiving light path is composed of aspheric mirror, concave grating and multiplier phototube. There located an interference filter in front of laser source and sample pool in front of the filter and aspheric mirror in front of sample pool and concave grating in front of aspheric mirror and multiplier phototube in front of concave grating. The said multiplier phototube is connected with input or output interfaces of signal processor. Comparing with current technique, this invention adopts concave grating chromatic dispersion to greatly increase the wavelength accuracy and at the same time adopts aspheric reflection and effective signal multiplication to ensure the accuracy and specificity of wavelength and a reliable result.

An optical spectrum analyzer measures to-be-measured light while carrying out calibration processing for correcting wavelength information of spectrum data of the to-be-measured light by a wavelength information correction device through a storage device based on the spectrum data of reference light that is obtained by causing the reference light whose wavelength is known to be incident on a tunable wavelength filter from light incident devices at all times together with the to-be-measured light. Since the optical spectrum analyzer can continuously measure the to-be-measured light in a wide wavelength range at high speed while maintaining high wavelength accuracy, it can continuously obtain the spectrum data of the to-be-measured light with high wavelength accuracy even if it is installed in a place in which an environment intensely changes.

The invention discloses a method for detecting sulfur dioxide in food, which comprises the following steps: 1) simply pretreating samples; 2) starting up, entering a main detection interface, clicking on a food quality analysis module and then entering a 'quantitative detection' interface, setting a 'detection item' as sulfur dioxide, and setting a 'product type' according to the actual product type; 3) operating according to the steps of sulfur dioxide detection instructions on the 'quantitative detection' interface of a instrument software; and 4) directly reading detection results. The invention is characterized in that: detecting personnel only need to simply pretreat the samples, and then carry out blank correction and sample detection so as to quickly obtain higher-accuracy quantitative analysis results of the index of sulfur dioxide in food. The method has simple operation, rapid detection speed, accurate detection results and high detection efficiency.

The present invention belongs to the technical field of elemental analysis, and more particularly, relates to a dynamic calibration method for echelle spectrometer in laser-induced breakdown spectroscopy, comprising: S1: collecting a standard light source by using an echelle spectrometer; S2: in combination with a calibration function, calculating a pixel position coordinate ({circumflex over (x)}, ŷ) corresponding to a spectral wavelength ŵ; S3: performing dynamic searching and filtering near the pixel position coordinate ({circumflex over (x)}, ŷ) to obtain a set D of all pixel position coordinates, and adjusting all original intensity values in the set D to obtain intensity values F(I_x,y), and S4: calculating a spectral line intensity value after dynamic calibration by summing the adjusted intensity values F(I_x,y), thereby completing dynamic calibration of the result of the echelle spectrometer. The method in the present invention can overcome the shortcoming, i.e., the existing echelle spectrometer is only calibrated before measurement without solving the spectral line drift during use, increasing the absolute intensity of the wavelength and reducing the detection limit of the quantitative analysis, as well as improving the precision of the quantitative analysis of an element to be analyzed.

A planar lightwave circuit generalized for handling any given band of multiple bands of a wavelength range, including a first grating element handling a first group of bands; and a second grating element handling a second group of bands. The first and second groups of bands overlap in the wavelength range, and may be spaced apart by a fixed wavelength value. By providing two periodic grating elements handling alternating bands, their free spectral range is allowed to expand, improving their roll-off characteristics. By providing separate inputs for each band, wavelength accuracy can be improved. Device flexibility can be further improved by using switch and interleaver fabrics at the inputs and outputs. The resultant device, generalized to handle any given band within a wavelength range, eliminates the need for separate component design and inventory tracking otherwise necessary.

The invention relates to a super-large viewing-field static polarization Fourier transform imaging method which comprises the following steps of: collecting, collimating and eliminating stray light for radiating light emitted by a target source through a front telescope system, and converting the radiating light into linearly polarized light through a polarizer; separating the linearly polarized light into two coherent and parallel partial light beams through a viewing-filed compensating polarization beam splitter; changing the vibration directions of the two partial light beams to be the same through an analyzer; and finally, converging the two light beams onto a detector for imaging and interference through an imaging mirror group to form an interference fringe modulated image containing spectrum information; and acquiring and processing received signals through a signal acquiring and processing system to acquire the image and the high spectral information of a target in a large vision angle.

The invention provides a generation method of a high-precision optical wavelength standard based on a femtosecond optical comb. The method comprises the following steps that 1, the pulse repeated frequency fr and the system frequency shift f0 of the femtosecond optical comb are locked into the microwave frequency standard; correction is performed to obtain the wavelength value corresponding to each comb tooth in the optical comb; 2, the wavelength signal of a certain comb tooth in the femtosecond optical comb and the optical signal output by a semiconductor laser are subjected to frequency beating processing and regulation to obtain the high-precision optical wavelength signal output used as an optical wave length standard source. By using the technical scheme, the femtosecond optical comb can output a series of standard optical wave lengths in a range from near infrared light to visible light spectrums; the semiconductor laser with the corresponding wavelength is matched; the optical wavelength standard covering the near infrared light to visible light spectrums can be built.

The invention relates to a handheld fluorescence detector which comprises a clamping groove, a first photoelectric switch, a second photoelectric switch, a light source, a light path system, and a photoelectric sensor, a signal amplification circuit, a peak holding circuit, a microprocessor and an analog-to-digital converter which are connected in order. The first photoelectric switch and the second photoelectric switch are mounted on the clamping groove and sequentially sense the reagent cards inserted into the clamping groove. The light path system comprises a first convex lens, a dichroic mirror, a second convex lens, an optical filter and a third convex lens; and light emitted by the light source sequentially penetrates through the first convex lens, is reflected to the second convex lens through the dichroic mirror, penetrates through the second convex lens and forms a light spot on a tested reagent card, and exciting light sequentially penetrates through the second convex lens, the dichroic mirror, the optical filter and the third convex lens to reach the photoelectric sensor. The detector is provided with a precise optical excitation and collection detection system, signals of the positions of the quality control line and the test line of the reagent card can be independently collected, the calculated amount is small, the speed is high, and the size of the detector can be smaller.

A spectrometer has a motor, a reduction means for employing a wave gear device to reduce the rotation of the motor, a wavelength dispersion device for being driven by rotation that was reduced by the reduction means, and a control means for controlling the operation of the motor. When changing the wavelength of light that is extracted from the spectrometer, the control means controls the motor so that an input shaft of the wave gear device is rotated by 180° or more before the input shaft is positioned at an angular position that corresponds to the target wavelength.