42results about How to "High wavelength resolution" patented technology

An apparatus for filtering electromagnetic waves, the apparatus comprising a substrate having a surface relief structure containing at least one dielectric body with physical dimensions smaller than the wavelength of the filtered electromagnetic waves, such structures repeated in a two dimensional array covering at least a portion of the surface of the first substrate. Also disclosed is a material sensor utilizing this apparatus.

The invention discloses a laser radar is based upon lame light source difference absorption process to test thickness of NO2 in the atmosphere, it includes lame light source, light incept and spectrum components, photo-detection and control transaction components, the characteristic is that the light incept and spectrum components accepts the scattered light from atmosphere backward by telescope tube of incept light, after coupling of light fiber, making the light to lay in the focal plane of lens, ripping into the raster by collimation lens, after section out the wave length of light 354.71nm and 360.00nm,recepted by the two emergent light fiber on the focal plane of lens. The raster is blazed grating, it has definite included angle with lens; the photo-detection and control transaction part includes microcomputer, data acquisition card, chronotron, enlarge shaping circuit, photomultiplier and photo-electricity probe. The invention has the beneficial purpose of easy structure, low cost, high diffraction efficiency, good flexibility, convenient using and vindicate etc.

An optical element of the present invention includes a structure having at least one convex portion and at least one concave portion formed so as to be adjacent to either one of the convex portions. At least one surface of the structure is covered, and the optical element has a hollow portion. At least one surface of the structure is covered with a covering layer formed by a deposition process.

The invention provides a dynamic strain measurement instrument based on multiple overlapped gratings. The dynamic strain measurement instrument comprises the multiple overlapped gratings, a wideband light source, a tunable filter, a positioning coupler, an etalon, a photoelectric detector and a demodulation and control circuit. The multiple overlapped gratings are formed in a way that a plurality of sensing gratings with center wavelengths being distributed at equal intervals are inscribed in an overlapped manner in a same area on a sensing optical fiber by selecting different phase templates, wherein the center wavelengths of a fiber Bragg grating, which are inscribed in the overlapped together, are continuously distributed at equal intervals within a wavelength scanning range of the tunable filter, so that sensing information of the same physical quantity to be measured can be continuously obtained for a plurality of times within each wavelength scanning period, and a peak value position and wavelength variation of each sensing grating in the multiple overlapped gratings, namely reconfigurable original dynamic strain signals, can be recorded. Therefore, the purpose of improving a measurement bandwidth of the dynamic strain signals based on a grating demodulation system of the tunable filter can be realized. According to the dynamic strain measurement instrument provided by the invention, the sensed measurement bandwidth of the fiber Bragg grating based on the tunable filter can be effectively improved, so that the high-speed and high-precision simultaneous measurement requirement of the dynamic strain signals can be met.

The invention is commonly (widely or generally) characterized in being an optical device, where a light waveguide is in the optical device and an inclined grating is in the optical device to couple in one or plural irradiating beams through guide mode; light irradiated from the inclined grating is focused into intermediate image in the preset position on a middle image plane, and the position of the intermediate image depends on light wavelength and effective refractive index of the guide mode. And the invention can place a spatial light modulator to control phase and / or amplitude of light beam. More remarkably, the invention comprises a last-stage focusing device to focus light transmitted by the spatial light modulator into last stage image in local region, so as to improve light strength, i.e. improving detecting sensitivity, where the last- stage focusing device can be a lens. And the invention also comprises a light receiver, which can be a optical fiber detector, or a last-stage image detecting light detector array.

The present invention discloses an F-P and FBG fiber sensor demodulation system, and aims to provide an F-P / FBG demodulation system which is high in wavelength resolution, and enables the demodulation precision to be improved. The F-P / FBG fiber sensor demodulation system of the present invention is realized by the following technical scheme that under the control of an operation control unit, a tunable laser emits out a beam of C-wave band laser of a constant wavelength, by an optical amplifier SOA and / or an optical isolator, and by being divided equally via a beam splitter, the incident light respectively irradiates to n F-P / FBG sensors in one-to-one correspondence, the light reflected by the F-P / FBG sensors is coupled to n phototriodes in one-to-one correspondence by n optical couplers, the optical power is converted into an optical current, the optical current is converted into an optical voltage entering an analog-digital converter by a logarithmic amplifier, the wavelength-reflection optical voltage digital quantity acquired in a time-sharing manner is stored in a memorizer of the operation control unit, the operation control unit carries out the fast Fourier transform on a sampled spectrum, the types of the F-P / FBG sensors are distinguished, and a peak searching demodulation algorithm is carried out to obtain a gradient value containing the cavity length information.

A method for increasing the wavelength resolution of optical performance monitor based on raster and detector array includes inputting optical signals via input port, distributing the optical spectrum space of said optical signals on the plane of detector array byoptical splitter, and processing and analyzing the measured data by data processing unit. It is characterized by that the spectrum of optical signals distributed in space is parallelly moved on said detector plane by a certain distance to make a same pixel to measure different wavelength values. Said distance is a N-th of the line width of pixle.

The invention discloses a quantum dot array spectrum sensor, comprising: a quantum dot colloidal array film and an array photoelectric detector; the quantum dot colloidal array film is used for bearing a quantum dot colloidal array; the quantum dot colloidal array includes a plurality of quantum dot colloidal units, wherein at least one quantum dot colloidal unit has a different absorbing or transmitting spectrum from other quantum dot colloidal units; the side of the quantum dot colloidal array film bearing the quantum dot colloidal array is opposite to a light-sensing side of the array photoelectric detector; after measured light of measured spectrum irradiates the quantum dot colloidal array film, transmitting light passing through the quantum dot colloidal array is detected by the light-sensing side. With the cooperation of the quantum dot colloidal array and the array photoelectric detector, the quantum dot array spectrum sensor has great bandwidth, high wavelength resolution and good sensitivity to weak light, and properties of existing instruments are improved greatly.

The invention discloses a metal-medium coupling resonance cavity for generating a Vaino resonance phenomenon. A branch resonance cavity in an MIM (metal-insulator-metal) waveguide and coupling resonance cavities of two baffles are adopted, and different resonance cavities are coupled to generate a steep asymmetric response spectrum line shape, so that the Vaino resonance phenomenon is obtained. In a transmittance spectrum, transmittance can quickly ascend from a valley to a peak of an asymmetric spectrum, so that under the condition that same switching contrast is obtained, required wavelength shift or interval is smaller than spectrum width of a symmetric similar Lorentzian line shape generated in a single resonance cavity, thereby being favorable for reducing a threshold value of a pump energy of a surface plasmon modulator or increasing a wavelength resolution rate of a surface plasmon wavelength division multiplexer and improving sensitivity of a biosensor. Therefore, the metal-medium coupling resonance cavity has very important application in fields of the surface plasmon modulator, a beam splitter, the wavelength division multiplexer and the sensor and the like.

The optical switch array is composed of multiple 1X(N+L) optical switch arrays, which is corresponding to each optical channel in each input optical waveguide. Optical switches based on array waveguide interferometer or wave selector are adopted in the first stage of switch array. The said optical switch is capable of separating a light wave in a certain wavelength from input waveguide singly without effecting on other light wave in another wavelength, and sends the separated light wave to any one piece of waveguide among N pieces of output waveguides or L pieces of buffered waveguides stage by stage. Buffered waveguides are in loop type. Output optical waveguides with identical serial number in 1X(N+L) optical switch arrays are connected to output port with serial number in devices. The invention realizes whole optical routes features optical buffering and optical gain, high integrity and available for mass manufacturing.

A tracking stage has an optical filter with a free spectral range greater than the maximum mode hop of a tunable laser. The free spectral range is sufficient to determine the wavelength of the laser output after the mode hop. The output is dithered or a quadrature signal is used to determine whether the mode hop is forwards or backwards. In a further embodiment, a second tracking stage with a shorter free spectral range is coupled to the tunable laser to provide enhanced wavelength resolution. Alternatively, the second tracking stage is omitted and the signal of the tracking stage is amplified to enhance wavelength resolution.

The invention relates to the technical field of laser alarm detection, specifically to a space-borne high-angle-resolution laser alarm detection method and apparatus. The system only needs one focal plane detector for realizing laser high-angle-resolution detection, and laser wavelength information is obtained through raster diffraction. The system has the advantages of compact structure, large view field, high angle resolution, great number of detection wavelengths and small sizes and is applicable to space-borne laser alarm. Measurement of wavelength and rough incident direction of the detected laser is realized through blazed grating, a short-focus lens and a focal plane detector. The rough measurement of the incident direction provides an incidence angle scope for high-precision angle measure through a lens array, in which each lens correspond to one small laser incidence angle scope, and each the small laser incidence angle scope corresponds to each pixel of the focal plane detector to realize high -resolution angle measurement. The angle positioning precision of a laser alarm system is substantially improved. The space-borne high-angle-resolution laser alarm detection method and apparatus are mainly applicable to laser detection.

An optical measurement apparatus operable with a test specimen has a light source with a laser having an output beam, and a beam splitter that splits the output beam of the laser into a first split beam and a second split beam. A test specimen holder holds the test specimen therein. A first optical fiber receives the first split beam and directs the first split beam against the test specimen in the test specimen holder. The apparatus further includes an instrumentation module. A second optical fiber receives the second split beam and conducts the second split beam to the instrumentation module. A third optical fiber receives signal light from the test specimen in the test specimen holder and conducts the signal light to the instrumentation module.

The present invention relates to an analysis apparatus 100 adapted to analyze measurement target components contained in a sample by irradiating a measurement cell 1 into which the sample is introduced with pulsed laser light, wherein the analysis apparatus 100 includes multiple semiconductor lasers 2 adapted to produce pulsed laser light at wavelengths absorbed by the measurement target components, a light detector 3 adapted to detect light emitted from the semiconductor lasers 2 and transmitted through the measurement cell 1, and a signal separation part 6 adapted to separate, from a light intensity signal obtained by the light detector 3, signals corresponding to a part of the pulses from the semiconductor lasers.

The invention relates to a spectrum testing system using a tunable laser light source. The spectrum testing system comprises the tunable laser light source, a light path part, a hardware part and an upper computer. An optical synchronization device composed of a band-pass filter and an etalon is arranged on the light path part. The tunable laser source is divided into two paths after power distribution is conducted through a 1*2 power coupler, wherein one path is used for synchronization, and the other path is connected with to-be-tested passive photoelectronic devices in all testing channels through a 1*N power coupler. Sampling circuits collect response signals of synchronization channels and the photoelectronic devices in all the testing channels in parallel, and send the response signals to the upper computer through a network to be processed. A server / client side framework is adopted for the upper computer. A server side program is responsible for synchronizing sampled data of all the channels, and a client side program is responsible for restoring true spectrum data of the to-be-tested passive photoelectronic devices in the first channel, the second channel...the Nth channel. By means of the spectrum testing system, multiple channels can conduct multi-channel spectrum analysis through one TLS light source in a multiplexing mode, and the system cost is reduced to an extremely large extent.

A collimator obtained by the alternate stacking of metal sheets 1 (40 μm thick) having holes 4 with a width of 2200 μm in the center thereof, and metal sheets 2 (10 μm thick) devoid of holes (the metal sheets 1 with the holes 4 are shown in the state in which they exist before being cut in the manner described below, the metal sheets 1 in the upper portion of the figure and the metal sheets in the bottom portion are not connected with each other in the finished product). The opposite sides are held by metal pressing sheets 3 that are 2 mm thick. These metal sheets and pressing sheets are bonded by means of diffusion bonding based on thermocompression bonding. The portions with the vertical through-holes 4 (40 μm×2000 μm) thus become light-transmitting portions, the metal sheets 2 serve as partitions between adjacent holes 4, and light collimated to a width of 40 μm can ultimately pass through. A compact collimator having high wavelength resolution without wavelength dependence can thus be achieved.

The invention relates to a method for improving wavelength resolution of a spatial spectrum separated wave filter. The wave filter comprises an input waveguide, a wave filter module functional block and an output waveguide. Under a precondition that the inner design of the spatial spectrum separated wave filter is unchanged, bandwidth of the wave filter is compressed through changing mode field coupling characteristics of an input collimator and an output collimator, thereby improving resolution of the wave filter. Input and output single-mode waveguides with different mode field diameters are utilized. Different collimator lens characteristics are utilized. The single-mode waveguides are commonly single-mode fibers. According to the method, under a precondition that the inner optical path design is unchanged, wavelength resolution capability of a fiber-and-grating type spectrum processing and analyzing product is remarkably improved through changing the characteristics of an input fiber, an output fiber and a collimating system, and FWHM of the product is compressed by about 20%.

The invention belongs to the technical field of laser alarm structures, and particularly relates to a broadband laser alarm structure based on a dichroscope and grating diffraction. The system comprises a front view field compression optical system, a dichroscope, a visible light blazed grating, a near-infrared light blazed grating, a first rear focusing optical system, a second rear focusing optical system, a near-infrared light focal plane detector and a visible light focal plane detector, and the dichroscope is arranged on one side of the front view field compression optical system; a visible light blazed grating, a second rear focusing optical system and a visible light focal plane detector are sequentially arranged on one side of the dichroscope, and a near-infrared light blazed grating, a first rear focusing optical system and a near-infrared light focal plane detector are sequentially arranged on the other side of the dichroscope. The grating diffraction method is adopted to realize laser wavelength detection, and has the advantages of high wavelength resolution, wide detection wave band and the like. The invention is used for laser warning.

The invention belongs to the technical field of laser detection, and relates to a laser sensing system and method. The system comprises a signal identification module and a plurality of laser detection modules, wherein the plurality of laser detection modules are arranged at different positions of a protection target; each laser detection module receives the incident laser at the corresponding position, converts the incident laser into a voltage signal and sends the voltage signal to the signal identification module; the signal identification module receives the plurality of voltage signals, judges whether the voltage of each voltage signal meets a corresponding preset voltage condition or not, and generates a corresponding trigger signal according to each voltage signal meeting the corresponding preset voltage condition; and the signal identification module also acquires the identifiers of the laser detection modules corresponding to the trigger signals, and identifies the wavelengthof the incident laser and the attacked position information of the protection target according to the identifiers of the plurality of laser detection modules. The system is simple in structure, low inmanufacturing cost, capable of rapidly and accurately identifying attacked laser information and high in portability.

The invention provides a dynamic strain measurement instrument based on multiple overlapped gratings. The dynamic strain measurement instrument comprises the multiple overlapped gratings, a wideband light source, a tunable filter, a positioning coupler, an etalon, a photoelectric detector and a demodulation and control circuit. The multiple overlapped gratings are formed in a way that a plurality of sensing gratings with center wavelengths being distributed at equal intervals are inscribed in an overlapped manner in a same area on a sensing optical fiber by selecting different phase templates, wherein the center wavelengths of a fiber Bragg grating, which are inscribed in the overlapped together, are continuously distributed at equal intervals within a wavelength scanning range of the tunable filter, so that sensing information of the same physical quantity to be measured can be continuously obtained for a plurality of times within each wavelength scanning period, and a peak value position and wavelength variation of each sensing grating in the multiple overlapped gratings, namely reconfigurable original dynamic strain signals, can be recorded. Therefore, the purpose of improving a measurement bandwidth of the dynamic strain signals based on a grating demodulation system of the tunable filter can be realized. According to the dynamic strain measurement instrument provided by the invention, the sensed measurement bandwidth of the fiber Bragg grating based on the tunable filter can be effectively improved, so that the high-speed and high-precision simultaneous measurement requirement of the dynamic strain signals can be met.