CN112147102A - AOTF-based transmitting-receiving integrated fiber spectrometer and implementation method - Google Patents
AOTF-based transmitting-receiving integrated fiber spectrometer and implementation method Download PDFInfo
- Publication number
- CN112147102A CN112147102A CN202011089265.5A CN202011089265A CN112147102A CN 112147102 A CN112147102 A CN 112147102A CN 202011089265 A CN202011089265 A CN 202011089265A CN 112147102 A CN112147102 A CN 112147102A
- Authority
- CN
- China
- Prior art keywords
- light
- spectrum
- optical fiber
- spectrometer
- aotf
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000835 fiber Substances 0.000 title claims abstract description 26
- 238000000034 method Methods 0.000 title claims abstract description 13
- 238000001228 spectrum Methods 0.000 claims abstract description 61
- 239000013307 optical fiber Substances 0.000 claims abstract description 57
- 238000001514 detection method Methods 0.000 claims abstract description 48
- 239000007788 liquid Substances 0.000 claims abstract description 13
- 239000007787 solid Substances 0.000 claims abstract description 12
- 238000012545 processing Methods 0.000 claims description 15
- 238000006243 chemical reaction Methods 0.000 claims description 14
- 229910052736 halogen Inorganic materials 0.000 claims description 14
- 150000002367 halogens Chemical class 0.000 claims description 14
- 238000004891 communication Methods 0.000 claims description 12
- 238000005057 refrigeration Methods 0.000 claims description 9
- 230000003595 spectral effect Effects 0.000 claims description 9
- 230000003321 amplification Effects 0.000 claims description 8
- 238000005259 measurement Methods 0.000 claims description 8
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 8
- 230000005540 biological transmission Effects 0.000 claims description 6
- 238000010521 absorption reaction Methods 0.000 claims description 4
- 230000003287 optical effect Effects 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 238000007405 data analysis Methods 0.000 claims description 2
- 239000000463 material Substances 0.000 claims description 2
- 230000010287 polarization Effects 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 claims description 2
- 230000005477 standard model Effects 0.000 claims description 2
- 238000012360 testing method Methods 0.000 claims description 2
- 238000013480 data collection Methods 0.000 claims 1
- 239000006185 dispersion Substances 0.000 claims 1
- 239000000126 substance Substances 0.000 abstract description 3
- 238000000862 absorption spectrum Methods 0.000 abstract 1
- 238000012544 monitoring process Methods 0.000 abstract 1
- 239000000523 sample Substances 0.000 description 18
- 238000005516 engineering process Methods 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000004856 soil analysis Methods 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/12—Generating the spectrum; Monochromators
- G01J3/1256—Generating the spectrum; Monochromators using acousto-optic tunable filter
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/42—Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry
- G01J3/433—Modulation spectrometry; Derivative spectrometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/359—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using near infrared light
Landscapes
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The invention discloses an AOTF-based transmitting-receiving integrated fiber spectrometer and an implementation method thereof. The spectrometer is based on the electric control light splitting characteristic of an acousto-optic tunable filter, a built-in active light source is utilized to be split and then is converged into a transmitting optical fiber, the receiving optical fiber is connected with a receiving device, the transmitting optical fiber and the receiving optical fiber can realize solid or liquid absorption spectrum detection by connecting different accessories, real-time spectrum calibration and light source performance monitoring are realized by adopting dual-detector beam splitting reference calibration, and +/-1-level diffraction light enters the same optical fiber to be conducted and irradiated on the surface of a sample by adding 0-level light shielding, a beam splitter and a concave reflector, so that the energy of signal light is enhanced, and the signal-to-noise ratio of spectrum detection is further improved. The invention has compact structure, high detection speed and high signal-to-noise ratio, can measure solid and liquid substances by connecting different optical fiber accessories, can realize detection far away from an instrument by combining long optical fibers, and has wide application range.
Description
Technical Field
The invention relates to a spectrum detection technology, in particular to an AOTF-based receiving and transmitting integrated fiber spectrometer and an implementation method thereof, which are suitable for the field of substance spectrum detection and analysis.
Background
The spectral analysis technology is taken as a representative of 'green detection technology' and has the advantages of high efficiency, high speed, low cost, no damage, environmental protection and the like, and AOTF (audible-optical tunable filter) is taken as a light splitting system and is known as 'the most prominent progress in the 90 s' in a near-infrared spectrometer. Based on the characteristics of AOTF: the appearance is light and small, and the design of double light paths is realized; the method has high precision, effectively eliminates the interference of the background and has strong anti-interference capability; the reproducibility is good, and the real-time rapid detection is realized; the scanning is controlled by an electronic signal, and the resolution is high; the wavelength switching speed is high in the full spectrum scanning range, and the stability is good; the signal energy is large; there are no moving parts. Therefore, the AOTF type spectrometer has the characteristics of flexibility, lightness, convenience for on-line analysis and the like, and is more and more widely applied to the fields of agriculture, food detection, soil analysis, water quality detection and the like.
The published literature and patent have a method for performing spectrum detection based on AOTF spectral characteristics, for example, application publication No. CN109115682A discloses a spectrometer for simultaneously detecting liquid and solid components and a detection method thereof, the patent uses an active polychromatic light source to converge and irradiate on the surface of a sample, receives diffuse reflection light on the surface of the sample and enters AOTF for light division, filters + 1-order diffraction light and 0-order light through a Glan prism, only-1-order diffraction light is detected and converged and enters a detector to realize spectrum detection, the-1-order diffraction light energy is wasted, the area of the sample surface irradiated by the spectrometer is small, the detection result is easy to cause inaccuracy, the method detects the sample before AOTF is subjected to spectrum detection, stray light is easy to introduce, and liquid measurement can only be performed by using a cuvette for sampling; application publication No. CN205898677U discloses an acousto-optic modulation dual-optical path dual-detector type near-infrared spectrometer, which adopts a dual-optical path dual-detector design, monochromatic light split by an acousto-optic tunable filter is divided into reference light and measurement light with controllable energy splitting ratio by an adjustable beam splitter for detection, however, 0-level light is not processed, and a noise substrate is easily generated to influence the signal-to-noise ratio.
Disclosure of Invention
Aiming at the prior art, the invention mainly solves the technical problems that: the +/-1 level signal light separated by the AOTF can not be fully utilized, the signal-to-noise ratio of the instrument is reduced, and the application scene of the instrument is not flexible and can only be detected in a specific place. The invention fully utilizes +/-1-level signal light, integrates the irradiation and the receiving of a signal light source by adopting an external optical fiber interface, can realize the detection of different samples such as solid, liquid and the like by accessing different detection accessories while improving the signal-to-noise ratio of the instrument, can realize the detection far away from the instrument by using a long optical fiber, and expands the application range of the instrument.
The invention aims to provide a receiving and transmitting integrated optical fiber spectrometer based on AOTF and an implementation method, based on the light splitting function of an electric control light splitting device such as an acousto-optic tunable filter, monochromatic light generated by a light source light splitting module is used for being conducted and irradiated on a sample through an optical fiber, diffuse scattered light of the sample or transmitted light of an object to be detected enters a detector through a receiving optical fiber, so that the spectral characteristic of signal light of the sample is detected, meanwhile, a part of the signal light is divided before the sample is irradiated for standard calibration spectral detection, the two are compared, the component information of the object to be detected is analyzed, through adding space shielding of 0-level light, 2 light splitting sheets and a concave reflector, the +/-1-level diffracted light is fully received, the energy of the signal light is effectively increased, the characteristic that a phase locking circuit is insensitive to the 0-level light is utilized, the signal to noise ratio of the spectral detection is improved, meanwhile, different detection accessories are accessed to realize, the long optical fiber can be used for realizing detection far away from an instrument, and has the advantages of wide application range, compact structure, high detection speed and high precision.
The light source light splitting module 1 consists of a wide-spectrum halogen light source 11, a collimating lens group 12, an acousto-optic tunable filter 13, a primary converging lens group 14 and a 0-level light baffle 15; the light beam emitted by the wide-spectrum halogen light source 11 is collimated light through the collimating lens group 12 and enters the acousto-optic tunable filter 13, when the acousto-optic tunable filter 13 does not work, diffracted light cannot be generated, when the acousto-optic tunable filter 13 works at a certain radio frequency, light with a certain wavelength can be separated into two beams of single-wavelength diffracted light with orthogonal polarization and one beam of 0-order polychromatic light, the three beams of light are converged and separated after passing through the primary converging lens group 14, the 0-order light is shielded by the 0-order light baffle 15, and +/-1-order diffracted light is emitted from two sides.
The wide-spectrum halogen light source 11 is a halogen bulb with a lens at the front end;
the collimating lens group 12 is a 2-piece lens group with a small aperture diaphragm inside, and the surface of the lens is plated with a wave band antireflection film suitable for a spectrometer.
The acousto-optic tunable filter 13 is a spectrometer light splitting device, and has no interior achromatic design, and can separate 0-order polychromatic light and +/-1-order monochromatic diffracted light with a certain included angle.
The primary converging lens group 14 is a 2-piece lens group and is used for converging light beams split by the acousto-optic tunable filter 13, and the surface of the lens is plated with a wave band antireflection film suitable for a spectrometer.
The +/-1-level signal light reference and emission module 2 consists of a-1-level flat plate light splitter 21, a + 1-level flat plate light splitter 22, a secondary converging lens 23, a reference detector 24, a-1-level concave reflector 25, a + 1-level concave reflector 26 and an emission optical fiber interface 27; the plus or minus 1 order diffracted light is respectively reflected in sequence through the common light path of the-1 order flat plate light-splitting sheet 21 and the +1 order flat plate light-splitting sheet 22 to enter the secondary converging lens 23 and the reference detector 24 to finish reference calibration detection, and the plus or minus 1 order diffracted light transmitted by the-1 order flat plate light-splitting sheet 21 and the +1 order flat plate light-splitting sheet 22 is respectively converged into the transmitting optical fiber interface 27 through the-1 order concave reflector 25 and the +1 order concave reflector 26.
The-1-level flat plate light-splitting sheet 21 and the + 1-level flat plate light-splitting sheet 22 are plane window sheets, the surfaces of which are plated with the applicable wave bands of the spectrometer and are provided with transmission and reflection films in a ratio of 90: 10.
The secondary converging lens 23 is 1 plano-convex lens, and the surface of the lens is plated with an antireflection film of a waveband suitable for a spectrometer.
The reference detector 24 is a unit detector corresponding to the applicable waveband of the spectrometer.
The surfaces of the-1-level concave reflector 25 and the + 1-level concave reflector 26 are plated with wave band reflecting films suitable for a spectrometer.
The transmitting optical fiber interface 27 is an SMA optical fiber interface.
The external detection accessory 3 consists of a solid diffuse reflection optical fiber measurement accessory 31 and a liquid transmission optical fiber measurement accessory 32; during testing, one end of the solid diffuse reflection optical fiber measuring accessory 31 or the liquid transmission optical fiber measuring accessory 32 is connected to the emission optical fiber interface 27 through an optical fiber, so that signal light can be irradiated on a solid or liquid sample.
The spectrum receiving module 4 consists of an incident optical fiber interface 41, a receiving lens group 42 and a receiving detector 43; the other end of the external accessory 3 is connected to the incident optical fiber interface 41 through an optical fiber, and the signal light reflected or transmitted by the sample to be detected enters the incident optical fiber interface 41 through the optical fiber and is collected by the receiving lens group 42 to enter the receiving detector 43, so that the material characteristic spectrum detection is realized.
The incident optical fiber interface 41 adopts the same interface as the emission optical fiber interface (27).
The receiving lens group 42 is a 3-piece lens group, and the surface of the lens is plated with a wave band antireflection film suitable for a spectrometer.
The receiving detector 43 employs the same unit detector as the reference detector (24).
The data acquisition and control module 5 consists of a main control module 51, a radio frequency power amplifier 52, an analog signal processing circuit 53, a reference detector preamplifier circuit 54 and a receiving detector preamplifier circuit 55, wherein the main control module 51 further comprises a computer 511, a USB communication circuit 512, an FPGA main control circuit 513, a radio frequency driving signal generating circuit 514, a TEC closed-loop refrigerating circuit 515, a reference light path A/D conversion circuit 516 and a receiving light path A/D conversion circuit 517; when the spectrum detector works, the computer 511 in the main control module 51 sends a spectrum acquisition instruction to the USB communication circuit 512, and the FPGA main control circuit 513 controls the spectrum acquisition system to work; the FPGA main control circuit 513 controls the radio frequency driving signal generating circuit 514 to generate a radio frequency signal with a required frequency, modulates the radio frequency signal and outputs the radio frequency signal, amplifies the radio frequency signal by the radio frequency power amplifier 53, and applies the radio frequency signal to the acousto-optic tunable filter 13; the FPGA main control circuit 513 controls the TEC closed-loop refrigeration circuit 515 to perform closed-loop refrigeration control on the infrared detector; the analog signal processing circuit 54 performs phase-locked amplification processing on weak modulation spectrum signals received by the reference detector front discharge circuit 54 and the receiving detector front discharge circuit 55, the FPGA main control circuit 513 controls the reference light path a/D conversion circuit 516 and the receiving light path a/D conversion circuit 517 to perform a/D conversion on the spectrum signals output by the analog signal processing circuit 54, and the FPGA main control circuit 513 packs the spectrum data and then sends the packed spectrum data to the computer 511 through the USB communication circuit 512; the optical signal received by the detector is amplified by adopting a phase-locked amplification mode, the gain of the system can be adjusted in a program-controlled manner, and the signal-to-noise ratio and flexibility of spectrum acquisition are improved on the premise of ensuring the sampling speed.
A sight line method of a receiving and transmitting integrated fiber optic spectrometer based on AOTF is characterized by comprising the following steps:
1) self-check on equipment
Connecting a power supply to supply power to the wide-spectrum halogen light source 11 and the data acquisition and control module 5, connecting the computer 511 and the USB communication circuit 512, and opening the upper computer software to establish communication connection with the spectrometer;
2) preheating of the apparatus, preparation before operation
2-1) opening a TEC closed-loop refrigeration circuit 515 to carry out closed-loop refrigeration control on the reference detector 24 and the receiving detector 43 until the detector is refrigerated stably;
2-2) the light signal output by the wide-spectrum halogen light source 11 after being powered on for a period of time is more stable, and a sample to be tested is placed in the optical fiber accessory connecting the emission optical fiber interface 27 and the incidence optical fiber interface 41.
3) Spectral data acquisition
3-1) the FPGA main control circuit 513 controls the radio frequency driving signal generating circuit 514 to work, applies radio frequency driving signals with different frequencies to the acousto-optic tunable filter 13, performs spectrum scanning on scattered light with different wavelengths of a measured object, and simultaneously detects monochromatic light split by the acousto-optic tunable filter 13 and monochromatic light diffusely reflected by a sample to be measured through the reference detector 24 and the receiving detector 43;
3-2) weak light signals detected by the reference detector 24 and the receiving detector 43 synchronously enter the analog signal processing circuit 53 after being amplified by a preceding stage, the FPGA main control circuit 513 synchronously controls the reference light path A/D conversion circuit 516 and the receiving light path A/D conversion circuit 517 to sample and store signals output by the analog signal processing circuit 53, and the reference calibration spectrum and the target spectrum are transmitted to an upper computer through the USB communication circuit 512 after the full spectrum scanning is finished;
4) data analysis and processing
4-1) calculating an absorption rate curve of the sample to be measured in the measurement wavelength range by comparing the reference calibration spectrum curve with the target spectrum curve;
4-2) comparing the absorption rate curve of the sample to be detected with the standard model to judge the components and the content of the sample to be detected.
The advantages of the invention are mainly reflected in that: 1. 0-order light generated after AOTF light splitting is shielded, and +/-1-order diffracted light is reflected to the same light path through 2 plane light splitting sheets to be received as a reference, so that the light source stability can be calibrated, detected and monitored in real time; 2. irradiating plus or minus 1-order diffraction light to the same position of an emission optical fiber interface by using 2 plane mirrors, fully utilizing the plus or minus 1-order diffraction light, enhancing the light intensity of a detection signal and improving the signal-to-noise ratio; 3. the detection of different samples such as solid and liquid is realized by accessing different detection accessories, the detection of a remote instrument can be realized by using a long optical fiber, the application range of the instrument is expanded, and the spectrum detection method based on the model can be utilized in other optical detection fields, so that the spectrum detection method has important application value and reference significance.
Drawings
FIG. 1 is a schematic diagram of the overall structure of the apparatus.
Fig. 2 is a schematic diagram of the working principle of the data acquisition and control module 5.
Detailed Description
An AOTF-based transmitting-receiving integrated fiber spectrometer comprises a light source light splitting module 1, a +/-1-level signal light reference and emitting module 2, an external detection accessory 3, a spectrum receiving module 4 and a data acquisition and control module 5, wherein the external detection accessory 3, the spectrum receiving module 4 and the data acquisition and control module 5 are shown in figure 1 and are used for explaining the structural characteristics and the implementation method of the AOTF-based transmitting-receiving integrated fiber spectrometer.
The main components used in the present invention are described below:
1) broad spectrum halogen light source 11: in the embodiment, the wide-spectrum halogen light source 11 adopts a stable infrared tungsten light source of Thorlabs company, and the spectral range is 350-2500 nm.
2) A collimating lens group 12, a primary converging lens group 14, a secondary converging lens 23, a-level 1 flat-plate beam splitter 21, a + level 1 flat-plate beam splitter 22, a-level 1 concave reflector 25, a + level 1 concave reflector 26 and a receiving lens group 42: the collimating lens group 12, the primary converging lens group 14, the secondary converging lens 23, the-1-stage flat plate splitter 21, the + 1-stage flat plate splitter 22, the-1-stage concave reflector 25, the + 1-stage concave reflector 26 and the receiving lens group 42 adopted in the embodiment are all self-designed components, and the wavelength range of the self-designed components is 1100-2300nm, so that the collimation, the convergence, the transflective and the receiving of the diffuse reflection signal light of the light path are realized.
3) Acousto-optic tunable filter 13: the acousto-optic tunable filter 13 used in this embodiment is a product customized by research institute 26 of the china electronic technology group, and its main technical indexes are:
a) the working wavelength is as follows: 1100nm-2300nm
b) Spectral resolution: 2nm-12nm
c) First-order deflection angle: 2.6 degree
d) Separation angle: 6.1 ° >
e) Diffraction efficiency: 60% >, a
f) Size: 560mm 400mm 315mm
g) Driving power: 2W
h) Driving frequency range: 37MHz-112MHz
4) Reference probe 24 and receiving probe 43: in the embodiment, a Judson J23TE2-66C type InGaAs infrared detection device is selected, and the main technical indexes are as follows: having a photosensitive area of
The spectral response range is 0.9-2.5 mu m, and the maximum value of dark current is 1.0E-5A; detection rate: 8.4E11cmHz1/2W-1And 2-stage TEC refrigeration.
The invention relates to a receiving and transmitting integrated optical fiber spectrometer based on AOTF, which has the characteristics of compact structure, small volume, high signal-to-noise ratio, high accuracy, simple detection method and the like, compared with the traditional AOTF spectrum detection method, the stability of a light source can be calibrated and detected in real time by shielding 0-level light generated after AOTF light splitting and reflecting +/-1-level diffraction light to the same light path through 2 plane light splitting sheets for reference reception, the +/-1-level diffraction light is irradiated to the same position of an emission optical fiber interface by using 2 concave reflectors, the +/-1-level diffraction light is fully utilized, the light intensity of a detection signal is enhanced, the signal-to-noise ratio is improved, solid and liquid substances can be measured by connecting different optical fiber accessories, the detection of a far-away instrument can be realized by combining long optical fibers, and the application range.
Claims (19)
1. An AOTF-based receiving and transmitting integrated fiber spectrometer comprises a light source light splitting module (1), a +/-1-level signal light reference and emitting module (2), an external detection accessory (3), a spectrum receiving module (4) and a data acquisition and control module (5); the method is characterized in that:
the light source light splitting module (1) provides an active light source and splits the light to generate 0-level and +/-1-level signal light, then +/-1-level signal light enters the +/-1-level signal light reference and emitting module (2), one part of the +/-1-level signal light is used for reference calibration, the other part of the +/-1-level signal light enters the external detection accessory (3) to irradiate on a sample, signal light generated by the sample through diffuse reflection enters the spectrum receiving module (4) to carry out sample spectrum collection and detection, and the data collection and control module (5) is used for controlling the operation of the whole machine and the collection and processing of the spectrum.
2. The AOTF-based all-in-one fiber optic spectrometer of claim 1, wherein:
the light source light splitting module (1) consists of a wide-spectrum halogen light source (11), a collimating lens group (12), an acousto-optic tunable filter (13), a primary converging lens group (14) and a 0-level light baffle (15); a light beam emitted by the wide-spectrum halogen light source (11) emits collimated light through the collimating lens group (12) and enters the acousto-optic tunable filter (13), when the acousto-optic tunable filter (13) does not work, diffracted light cannot be generated, when the acousto-optic tunable filter (13) works at a certain radio frequency, light with a certain wavelength can be separated into two beams of single-wavelength diffracted light with orthogonal polarization and one beam of 0-order polychromatic light, the three beams of light are converged and separated after passing through the primary converging lens group (14), the 0-order light is blocked by the 0-order light baffle (15), and +/-1-order diffracted light is emitted from two sides.
3. The AOTF-based all-in-one fiber optic spectrometer of claim 2, wherein: the wide-spectrum halogen light source (11) is a halogen bulb with a lens at the front end;
4. the AOTF-based all-in-one fiber optic spectrometer of claim 2, wherein: the collimating lens group (12) is a 2-piece lens group with a small-hole diaphragm inside, and the surface of the lens is plated with a wave band antireflection film suitable for a spectrometer.
5. The AOTF-based all-in-one fiber optic spectrometer of claim 2, wherein: the acousto-optic tunable filter (13) is a spectrometer light splitting device, and the interior of the acousto-optic tunable filter is not designed with achromatic dispersion, so that 0-order polychromatic light and +/-1-order monochromatic diffraction light with a certain included angle can be separated.
6. The AOTF-based all-in-one fiber optic spectrometer of claim 2, wherein: the primary converging lens group (14) is a 2-piece lens group and is used for converging light beams split by the acousto-optic tunable filter (13), and the surface of the lens is plated with a wave band antireflection film suitable for a spectrometer.
7. The AOTF-based all-in-one fiber optic spectrometer of claim 1, wherein:
the +/-1-level signal light reference and emission module (2) consists of a-1-level flat plate light splitting sheet (21), a + 1-level flat plate light splitting sheet (22), a secondary converging lens (23), a reference detector (24), a-1-level concave reflector (25), a + 1-level concave reflector (26) and a transmitting optical fiber interface (27); the plus or minus 1-order diffracted light is respectively reflected into a secondary converging lens (23) and a reference detector (24) in sequence through a common light path of a-1-order flat plate light-splitting sheet (21) and a + 1-order flat plate light-splitting sheet (22) to finish reference calibration detection, and the plus or minus 1-order diffracted light transmitted by the-1-order flat plate light-splitting sheet (21) and the + 1-order flat plate light-splitting sheet (22) is respectively converged into a transmitting optical fiber interface (27) through a-1-order concave reflecting mirror (25) and a + 1-order concave reflecting mirror (26).
8. The AOTF-based all-in-one fiber optic spectrometer of claim 7, wherein: the-1-level flat plate light splitting sheet (21) and the + 1-level flat plate light splitting sheet (22) are plane window sheets, the surface of the plane window sheet is plated with a spectrometer applicable waveband, and the plane window sheet is provided with a transmission and reflection film with a ratio of 90: 10.
9. The AOTF-based all-in-one fiber optic spectrometer of claim 7, wherein: the secondary converging lens (23) is 1 plano-convex lens, and the surface of the lens is plated with a wave band antireflection film suitable for a spectrometer.
10. The AOTF-based all-in-one fiber optic spectrometer of claim 7, wherein: the reference detector (24) is a unit detector corresponding to the applicable waveband of the spectrometer.
11. The AOTF-based all-in-one fiber optic spectrometer of claim 7, wherein: the surfaces of the-1-level concave reflector (25) and the + 1-level concave reflector (26) are plated with a spectrum meter applicable waveband reflecting film.
12. The AOTF-based all-in-one fiber optic spectrometer of claim 7, wherein: the transmitting optical fiber interface (27) is an SMA optical fiber interface.
13. The AOTF-based all-in-one fiber optic spectrometer of claim 1, wherein:
the external detection accessory (3) consists of a solid diffuse reflection optical fiber measurement accessory (31) and a liquid transmission optical fiber measurement accessory (32); during testing, one end of the solid diffuse reflection optical fiber measuring accessory (31) or the liquid transmission optical fiber measuring accessory (32) is connected with the emission optical fiber interface (27) through an optical fiber, and then signal light can be irradiated on a solid or liquid sample.
14. The AOTF-based all-in-one fiber optic spectrometer of claim 1, wherein:
the spectrum receiving module (4) consists of an incident optical fiber interface (41), a receiving lens group (42) and a receiving detector (43); the signal light reflected or transmitted by the sample to be detected enters an incident optical fiber interface (41) through an optical fiber, is collected by a receiving lens group (42) and enters a receiving detector (43), and therefore material characteristic spectrum detection is achieved.
15. The AOTF-based all-in-one fiber optic spectrometer of claim 14, wherein: the incident optical fiber interface (41) adopts the same interface as the emission optical fiber interface (27).
16. The AOTF-based all-in-one fiber optic spectrometer of claim 14, wherein: the receiving lens group (42) is a 3-piece lens group, and the surface of the lens is plated with a wave band antireflection film suitable for a spectrometer.
17. The AOTF-based all-in-one fiber optic spectrometer of claim 14, wherein: the receiving detector (43) adopts the same unit detector as the reference detector (24).
18. The AOTF-based all-in-one fiber optic spectrometer of claim 1, wherein:
the data acquisition and control module (5) consists of a main control module (51), a radio frequency power amplifier (52), an analog signal processing circuit (53), a reference detector pre-amplification circuit (54) and a receiving detector pre-amplification circuit (55), wherein the main control module (51) also comprises a computer (511), a USB communication circuit (512), an FPGA main control circuit (513), a radio frequency driving signal generating circuit (514), a TEC closed-loop refrigerating circuit (515), a reference light path A/D conversion circuit (516) and a receiving light path A/D conversion circuit (517); when the spectrum detector works, a computer (511) in the main control module (51) sends a spectrum acquisition instruction to the USB communication circuit (512), and the FPGA main control circuit (513) controls the spectrum acquisition system to work; the FPGA main control circuit (513) controls the radio frequency driving signal generating circuit (514) to generate a radio frequency signal with required frequency, modulates the radio frequency signal and outputs the radio frequency signal, amplifies the radio frequency signal by the radio frequency power amplifier (53), and applies the radio frequency signal to the acousto-optic tunable filter (13); the FPGA main control circuit (513) controls the TEC closed-loop refrigeration circuit (515) to carry out closed-loop refrigeration control on the infrared detector; an analog signal processing circuit (54) performs phase-locked amplification processing on weak modulation spectrum signals received by a reference detector pre-amplification circuit (54) and a receiving detector pre-amplification circuit (55), an FPGA main control circuit (513) controls a reference light path A/D conversion circuit (516) and a receiving light path A/D conversion circuit (517) to perform A/D conversion on the spectrum signals output by the analog signal processing circuit (54), and the FPGA main control circuit (513) packs the spectrum data and then sends the spectrum data to a computer (511) through a USB communication circuit (512); the optical signal received by the detector is amplified by adopting a phase-locked amplification mode, the gain of the system can be adjusted in a program-controlled manner, and the signal-to-noise ratio and flexibility of spectrum acquisition are improved on the premise of ensuring the sampling speed.
19. A method for implementing an AOTF-based transmit-receive integrated fiber optic spectrometer as claimed in claim 1, characterized in that the method comprises the following steps:
1) self-check on equipment
Connecting a power supply to supply power to the wide-spectrum halogen light source (11) and the data acquisition and control module (5), connecting a computer (511) and a USB communication circuit (512), and opening upper computer software to establish communication connection with the spectrometer;
2) preheating of the apparatus, preparation before operation
2-1) opening a TEC closed-loop refrigeration circuit (515) to carry out closed-loop refrigeration control on a reference detector (24) and a receiving detector (43) until the detector is refrigerated stably;
2-2) the light signal output by the wide-spectrum halogen light source (11) after being electrified for a period of time is more stable, and a sample to be detected is placed in an optical fiber accessory connecting the emission optical fiber interface (27) and the incidence optical fiber interface (41);
3) spectral data acquisition
3-1) the FPGA main control circuit (513) controls the radio frequency driving signal generating circuit (514) to work, radio frequency driving signals with different frequencies are applied to the acousto-optic tunable filter (13), spectrum scanning is carried out on scattered light with different wavelengths of a measured object, and monochromatic light split by the acousto-optic tunable filter (13) and monochromatic light diffusely reflected by a sample to be measured are simultaneously detected by the reference detector (24) and the receiving detector (43);
3-2) weak light signals detected by the reference detector (24) and the receiving detector (43) synchronously enter the analog signal processing circuit (53) after being amplified by a preceding stage, the FPGA main control circuit (513) synchronously controls the reference light path A/D conversion circuit (516) and the receiving light path A/D conversion circuit (517) to sample and store signals output by the analog signal processing circuit (53), and a reference calibration spectrum and a target spectrum are transmitted to an upper computer through the USB communication circuit (512) after full spectrum scanning is finished;
4) data analysis and processing
4-1) calculating an absorption rate curve of the sample to be measured in the measurement wavelength range by comparing the reference calibration spectrum curve with the target spectrum curve;
4-2) comparing the absorption rate curve of the sample to be detected with the standard model to judge the components and the content of the sample to be detected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011089265.5A CN112147102A (en) | 2020-10-13 | 2020-10-13 | AOTF-based transmitting-receiving integrated fiber spectrometer and implementation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011089265.5A CN112147102A (en) | 2020-10-13 | 2020-10-13 | AOTF-based transmitting-receiving integrated fiber spectrometer and implementation method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112147102A true CN112147102A (en) | 2020-12-29 |
Family
ID=73953157
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011089265.5A Pending CN112147102A (en) | 2020-10-13 | 2020-10-13 | AOTF-based transmitting-receiving integrated fiber spectrometer and implementation method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112147102A (en) |
-
2020
- 2020-10-13 CN CN202011089265.5A patent/CN112147102A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN2874476Y (en) | Terahertz time domain spectral instrument based on optical rectification | |
| CN104483104B (en) | A kind of photo detector spectral response analysis system | |
| CN106441580A (en) | Terahertz time-domain spectrometer capable of variable-angle incidence and simultaneous measurement of transmission and reflection | |
| US20140016134A1 (en) | Miniaturized laser heterodyne radiometer for carbon dioxide, methane and carbon monoxide measurements in the atmospheric column | |
| CA2697824A1 (en) | Noise cancellation in fourier transform spectrophotometry | |
| CN111707634B (en) | Multichannel gas concentration detection system and method based on mid-infrared absorption spectrum | |
| CN208013060U (en) | A kind of more gas detecting systems of wave-length coverage and wavelength continuously adjustable | |
| CN108279209A (en) | A kind of more gas detecting systems of wave-length coverage and wavelength continuously adjustable | |
| CN105823755B (en) | It is a kind of that sensor-based system is absorbed from mixed gas based on tunable semiconductor laser | |
| CN108267420A (en) | Seed aqueous amount detection systems and method | |
| CN104458645A (en) | Method and system for realizing continuous terahertz spectrum detection | |
| CN106872402A (en) | Gas-detecting device and method based on super continuous spectrums laser | |
| CN202522516U (en) | Optical transmissivity test device | |
| CN112903611B (en) | Multiband absorbance detection system and working method thereof | |
| CN102928081B (en) | Acousto-optic adjustable filtering type near-infrared spectrometer | |
| CN106153575A (en) | A kind of acousto-optic modulation double light path double detector type near infrared spectrometer and method of testing | |
| CN110231307A (en) | Open light path gas concentration detection apparatus and method based on TDLAS technology | |
| CN213658575U (en) | Receiving and transmitting integrated optical fiber spectrometer based on AOTF | |
| CN211528208U (en) | Optical fiber gas concentration remote sensing detection device based on coherent detection method | |
| CN112147102A (en) | AOTF-based transmitting-receiving integrated fiber spectrometer and implementation method | |
| US20060060759A1 (en) | Method and apparatus for measurement of optical detector linearity | |
| CN107860749A (en) | Based on CO2The portable SF of laser6Leak remote sensing instrument | |
| US8766191B2 (en) | External/internal optical adapter for FTIR spectrophotometer | |
| CN106501184B (en) | Optical glass measuring device and measuring method thereof | |
| CN213658569U (en) | AOTF-based dual-detector ellipsoidal reflecting bowl receiving diffuse reflection spectrometer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |