CN110132886B - High-sensitivity terahertz spectrum detection device and method for liquid concentration - Google Patents
High-sensitivity terahertz spectrum detection device and method for liquid concentration Download PDFInfo
- Publication number
- CN110132886B CN110132886B CN201910554917.9A CN201910554917A CN110132886B CN 110132886 B CN110132886 B CN 110132886B CN 201910554917 A CN201910554917 A CN 201910554917A CN 110132886 B CN110132886 B CN 110132886B
- Authority
- CN
- China
- Prior art keywords
- terahertz
- liquid
- lens
- beam splitter
- silicon
- 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.)
- Active
Links
- 239000007788 liquid Substances 0.000 title claims abstract description 54
- 238000001514 detection method Methods 0.000 title claims abstract description 41
- 238000001228 spectrum Methods 0.000 title claims abstract description 16
- 238000000034 method Methods 0.000 title abstract description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 58
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 58
- 239000010703 silicon Substances 0.000 claims abstract description 58
- -1 polyethylene Polymers 0.000 claims abstract description 53
- 239000004698 Polyethylene Substances 0.000 claims abstract description 33
- 229920000573 polyethylene Polymers 0.000 claims abstract description 33
- 239000000758 substrate Substances 0.000 claims abstract description 26
- 238000007789 sealing Methods 0.000 claims abstract description 8
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000013078 crystal Substances 0.000 claims description 28
- 229910007709 ZnTe Inorganic materials 0.000 claims description 22
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 20
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 20
- 239000010409 thin film Substances 0.000 claims description 18
- 238000000411 transmission spectrum Methods 0.000 claims description 18
- 230000035945 sensitivity Effects 0.000 claims description 8
- 230000008878 coupling Effects 0.000 claims description 6
- 238000010168 coupling process Methods 0.000 claims description 6
- 238000005859 coupling reaction Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 6
- 230000000737 periodic effect Effects 0.000 claims description 6
- 238000002834 transmittance Methods 0.000 claims description 6
- 238000011088 calibration curve Methods 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 2
- 239000010408 film Substances 0.000 claims 1
- 238000004458 analytical method Methods 0.000 abstract description 6
- 238000010183 spectrum analysis Methods 0.000 abstract description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 18
- 239000000126 substance Substances 0.000 description 12
- 238000005516 engineering process Methods 0.000 description 6
- 230000008901 benefit Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 238000001328 terahertz time-domain spectroscopy Methods 0.000 description 3
- 239000003989 dielectric material Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 238000004611 spectroscopical analysis Methods 0.000 description 2
- 238000005411 Van der Waals force Methods 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004883 computer application Methods 0.000 description 1
- 239000002178 crystalline material Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000008204 material by function Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000001448 refractive index detection Methods 0.000 description 1
- 238000012916 structural analysis Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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
- G01N21/3577—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing liquids, e.g. polluted water
-
- 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
- G01N21/3581—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation
Landscapes
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Toxicology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The invention discloses a high-sensitivity terahertz spectrum detection device and method for liquid concentration, wherein the device comprises a terahertz metamaterial array structure, and is composed of a plurality of lithium tantalate medium cylinders, a medium substrate made of silicon, a polyethylene cover plate and a polyethylene sealing baffle plate, and liquid to be detected is arranged in a cavity which is arranged between the polyethylene cover plate and the silicon substrate and around the medium cylinder and used for storing the liquid to be detected. When the terahertz wave is incident from the polyethylene cover plate side, a terahertz wave response is obtained at the silicon substrate side, and then terahertz spectrum analysis is performed. The device has the characteristics of short detection time, capability of working at room temperature and the like, and simultaneously, the analysis device integrates a plurality of unit devices together, can efficiently perform terahertz spectrum analysis on the concentration change of the liquid to be detected, and has wide application potential in the aspect of measuring the concentration of the liquid.
Description
Technical Field
The invention belongs to the field of terahertz wave technology application, and particularly relates to a high-sensitivity terahertz spectrum detection device and method for liquid concentration.
Background
Terahertz wave (terahertz wave) means a frequency of 0.1 to 10.0THz (1 thz=10) 12 Hz), the wave band is near the microwave band and near the infrared band, the spatial resolution is better than that of the microwave, and the penetrability is stronger than that of the infrared. Terahertz waves have the characteristic of low photon energy (1 THz is about 4.1 meV), and do not generate ionization effect to destroy organisms and biological tissues. The terahertz spectrum of the substance has rich information, and because the energy levels of vibration and rotation of chemical molecules such as hydrogen bonds, van der Waals forces, dipole rotation and the like among molecules or inside the molecules correspond to the terahertz frequency band, and particularly a plurality of organic molecular energy levels are positioned in the frequency band, the molecules of the substance have unique transmission spectrums in the terahertz frequency band, so that the THz spectrum (including emission, reflection and transmission spectrums) of the substance contains rich physical and chemical information, and has important application values in the aspects of physics, chemistry, biomedicine, astronomy, material science, environmental science and the like.
Ferroelectric phase lithium tantalate crystals are "universal" materials in the field of functional materials. They have good mechanical and physical properties and low cost, and are widely used in the optical technology industry nowadays as nonlinear optical crystals, electro-optical crystals, piezoelectric crystals, acousto-optic crystals, birefringent crystals, etc. Previous work has shown that the structure of crystalline materials is closely related to their optical properties.
The spectrum analysis is mainly based on optical theory, and based on the interaction of substances and light, the correlation between the molecular structure of the substances and electromagnetic radiation is established, so that the analysis and identification of the geometrical isomerism, the stereoisomers, the conformational isomerism and the molecular structure of the substances are carried out. Spectroscopic analysis has become one of the main methods of molecular structural analysis and identification of substances in modern times. With the development of technology, technological innovations and computer applications, spectroscopic analysis has also been rapidly advancing. The spectrum analysis method has the characteristics of prominent advantages, wide application and the like, and is an indispensable tool in various scientific research and production fields. With the continuous improvement of technological development and analysis requirements, scientific researchers are also continuously innovating the spectrum analysis method. The spectrum analysis method has become a common analysis tool and an important analysis method for material analysis and identification because of the rapidness, sensitivity and accuracy, low requirements on environmental conditions and important functions on the refractive index detection of materials.
In recent years, THz technology has achieved a number of remarkable achievements with the development of terahertz radiation generation and detection technology. Metamaterials are increasingly being used as functional devices in terahertz applications such as absorbers, filters, modulators, sensors and polarizers. In particular, THz metamaterials have great potential in non-ionized biochemical sensing applications, not only because many substances have fingerprint spectra in the THz band. Moreover, compared with the conventional terahertz time-domain spectrometry, the terahertz metamaterial-based sensing measurement method has the advantages of simplicity and convenience and higher sensitivity. Therefore, the research of the terahertz sensor based on the metamaterial becomes a hot spot of the THz technology research.
Disclosure of Invention
The invention provides a high-sensitivity terahertz spectrum sensing detection device for liquid concentration, which aims to overcome the defects of the existing liquid concentration detection method, utilizes terahertz waves to analyze and detect the liquid concentration on the transmission characteristic of liquid, and meets the requirements of safety, high sensitivity, detection time period, convenient operation, capability of working at room temperature and the like.
The technical scheme of the invention is as follows:
a high-sensitivity terahertz spectrum detection device for liquid concentration comprises a femtosecond laser, a chopper, a beam splitter, a photoconductive antenna, a first parabolic mirror, a first polytetrafluoroethylene lens, a first silicon lens, a terahertz metamaterial array structure, a second silicon lens, a second polytetrafluoroethylene lens, a second parabolic mirror, a delay line, a first reflecting mirror, a second reflecting mirror, a thin film beam splitter, a ZnTe crystal, a quarter wave plate, a Wollaston prism, a photoelectric balance detector, a phase-locked amplifier and a computer; the terahertz metamaterial array structure comprises a silicon substrate, a medium cylinder, a polyethylene cover plate and a polyethylene sealing baffle; the medium cylinders are arranged between the polyethylene cover plate and the silicon substrate, two end faces of the medium cylinders are respectively abutted against the polyethylene cover plate and the silicon substrate, and a plurality of medium cylinders are in a periodic array structure; a cavity for storing liquid to be tested is arranged between the polyethylene cover plate and the silicon substrate and around the medium cylinder, and the cavity is sealed by a polyethylene sealing baffle between the polyethylene cover plate and the silicon substrate; the electromagnetic waves are coupled in the periodic array structure to obtain a specific terahertz transmission spectrum line, and the terahertz transmission spectrum line is obviously deviated due to the tiny changes of substances on the surface of the structure, so that the sensing effect on the liquid to be detected in the terahertz region can be enhanced, and the detection sensitivity of the terahertz transmission spectrum of the liquid with different concentrations is effectively improved.
Further, a chopper and a beam splitter are sequentially arranged on a laser light path generated by the femtosecond laser, and the beam splitter divides laser generated by the femtosecond laser into stronger pumping light and weaker detection light; the pump light is excited by the terahertz pulse through the photoconductive antenna, the terahertz pulse sequentially passes through the first parabolic mirror for collimation and the first polytetrafluoroethylene lens for focusing and then reaches the incident spherical surface of the first silicon lens, the terahertz pulse passes through the first silicon lens for coupling, penetrates through the polyethylene cover plate, enters a cavity for storing liquid to be tested, enters the incident plane of the second silicon lens through the silicon substrate, and is coupled and emitted from the emergent spherical surface of the second silicon lens, and the emergent terahertz pulse sequentially passes through the second polytetrafluoroethylene lens for collimation and the second parabolic mirror for focusing and then reaches the incident surface of the ZnTe crystal through the thin film beam splitter; a delay line, a first reflecting mirror, a second reflecting mirror and a thin film beam splitter are sequentially arranged on the detection light path; after being reflected by a thin film beam splitter, the detection light is converged with terahertz pulses on the incident surface of the ZnTe crystal, and then sequentially passes through the ZnTe crystal, the quarter wave plate and the Wollaston prism and is detected by a photoelectric balance detector; the photoelectric balance detector is connected with the computer through the phase-locked amplifier.
The invention also discloses a detection method of the high-sensitivity terahertz spectrum detection device for the liquid concentration, which comprises the following steps:
1) Adding liquid to be detected into the terahertz metamaterial array structure until the cavity for storing the liquid to be detected is fully filled;
2) Laser generated by the femtosecond laser passes through a chopper and a beam splitter, and the beam splitter divides the laser generated by the femtosecond laser into pump light and detection light; the pump light excites terahertz pulses through a photoconductive antenna, the terahertz pulses sequentially pass through a first parabolic mirror for collimation and a first polytetrafluoroethylene lens for focusing and then reach an incident spherical surface of the first silicon lens, the terahertz pulses pass through a polyethylene cover plate through the coupling of the first silicon lens, enter a cavity for storing liquid to be detected, enter an incident plane of a second silicon lens through a silicon substrate, are coupled and emergent from an emergent spherical surface of the second silicon lens, and the emergent terahertz pulses sequentially pass through the second polytetrafluoroethylene lens for collimation and the second parabolic mirror for focusing and then reach an incident surface of a ZnTe crystal through a thin film beam splitter; the detection light sequentially passes through the delay line, the first reflecting mirror, the second reflecting mirror and the thin film beam splitter, is converged with terahertz pulses on the incident surface of the ZnTe crystal, and then sequentially passes through the ZnTe crystal, the quarter wave plate and the Wollaston prism to be detected by the photoelectric balance detector; the measured electrical signals are amplified by a phase-locked amplifier and then sent to a computer, and the data information of the transmittance measured by the terahertz time-domain spectroscopy system is fitted by the computer to obtain the terahertz transmission spectrum of the liquid to be measured;
3) Taking the frequency corresponding to the point with the lowest transmittance in the terahertz transmission spectrum of the liquid to be measured as a resonance frequency point, wherein the positions of the resonance frequency point of the liquid to be measured and the concentration of the liquid to be measured are in one-to-one correspondence; and obtaining the concentration of the liquid to be measured according to a calibration curve between the resonance frequency point of the liquid to be measured and the concentration of the liquid to be measured.
The invention has the following advantages:
1) Because the terahertz photon energy is low, an ionization effect is not generated, so that the terahertz photon energy is safe to use and does not cause harm to human bodies;
2) The terahertz metamaterial array structure is formed by adopting all-dielectric materials, ohmic loss is avoided, and the result is more accurate;
3) The propagation speed of electromagnetic waves is the light speed, and the detection waiting time of the system is mostly the processing time of a computer on signals, so that the system has the advantage of short detection time;
4) The terahertz spectrum sensing detection device with high sensitivity of liquid concentration can generate electromagnetic waves at room temperature to detect a sample, and has the advantages of simple equipment and normal temperature detection;
the invention can be widely applied to the accurate measurement of the concentration of the liquid, can efficiently carry out concentration sensing on the liquid, and provides a convenient, quick and accurate detection device for the measurement of the liquid with unknown concentration.
Drawings
FIG. 1 is a block diagram of a high sensitivity terahertz spectrum detection device for liquid concentration in the invention;
FIG. 2 is a block diagram of the terahertz metamaterial array structure of the present invention;
fig. 3 is a schematic diagram of a three-layer structure of the terahertz metamaterial array structure in the front direction;
FIG. 4 is a terahertz transmission spectrum of the invention for detection of the concentration of an alcohol solution from 0% to 100%;
FIG. 5 is a calibration curve between the resonance frequency point of the alcohol and the alcohol concentration according to the present invention;
in the figure: the device comprises a femtosecond laser 1, a chopper 2, a beam splitter 3, a photoconductive antenna 4, a first parabolic mirror 5, a first polytetrafluoroethylene lens 6, a first silicon lens 7, a terahertz metamaterial array structure 8, a second silicon lens 9, a second polytetrafluoroethylene lens 10, a second parabolic mirror 11, a delay line 12, a first reflecting mirror 13, a second reflecting mirror 14, a thin film beam splitter 15, a ZnTe crystal 16, a quarter wave plate 17, a Wollaston prism 18, a photoelectric balance detector 19, a lock-in amplifier 20, a computer 21, a polyethylene cover plate 22, a silicon substrate 23, a single period 24 in the whole periodic array structure, a medium cylinder 25, a cavity 26 for storing liquid to be tested and a polyethylene sealing baffle 27.
Detailed Description
The invention is further illustrated by the following figures and examples:
as shown in fig. 1, a high-sensitivity terahertz spectrum sensing detection apparatus for liquid concentration includes a femtosecond laser 1, a chopper 2, a beam splitter 3, a photoconductive antenna 4, a first parabolic mirror 5, a first polytetrafluoroethylene lens 6, a first silicon lens 7, a terahertz metamaterial array structure 8, a second silicon lens 9, a second polytetrafluoroethylene lens 10, a second parabolic mirror 11, a delay line 12, a first reflecting mirror 13, a second reflecting mirror 14, a thin film beam splitter 15, a ZnTe crystal 16, a quarter wave plate 17, a wollaston prism 18, a photoelectric balance detector 19, a lock-in amplifier 20, and a computer 21.
As shown in fig. 2, the terahertz metamaterial array structure 8 comprises a silicon substrate 23, a dielectric cylinder 25, a polyethylene cover plate 22 and a polyethylene sealing baffle 27; the medium cylinders 25 are arranged between the polyethylene cover plate 22 and the silicon substrate 23, two end faces of the medium cylinders 25 are respectively abutted against the polyethylene cover plate 22 and the silicon substrate 23, and a plurality of medium cylinders are in a periodic array structure, and each period comprises four medium cylinders with equal size; a cavity 26 for storing liquid to be measured is arranged between the polyethylene cover plate 22 and the silicon substrate 23 and around the medium cylinder 25, and is sealed by a polyethylene sealing baffle 27 between the polyethylene cover plate 22 and the silicon substrate 23.
The electromagnetic waves are coupled in the periodic array structure to obtain a specific terahertz transmission spectrum line, and the terahertz transmission spectrum line is obviously deviated due to the tiny changes of substances on the surface of the structure, so that the sensing effect on the liquid to be detected in the terahertz region can be enhanced, and the detection sensitivity of the terahertz transmission spectrum of the liquid with different concentrations is effectively improved.
A chopper and a beam splitter are sequentially arranged on a laser light path generated by the femtosecond laser, and the beam splitter divides laser generated by the femtosecond laser into stronger pumping light and weaker detection light; the pump light is excited by the terahertz pulse through the photoconductive antenna, the terahertz pulse sequentially passes through the first parabolic mirror for collimation and the first polytetrafluoroethylene lens for focusing and then reaches the incident spherical surface of the first silicon lens, the terahertz pulse passes through the first silicon lens for coupling, penetrates through the polyethylene cover plate, enters a cavity for storing liquid to be tested, enters the incident plane of the second silicon lens through the silicon substrate, and is coupled and emitted from the emergent spherical surface of the second silicon lens, and the emergent terahertz pulse sequentially passes through the second polytetrafluoroethylene lens for collimation and the second parabolic mirror for focusing and then reaches the incident surface of the ZnTe crystal through the thin film beam splitter; a delay line, a first reflecting mirror, a second reflecting mirror and a thin film beam splitter are sequentially arranged on the detection light path; after being reflected by a thin film beam splitter, the detection light is converged with terahertz pulses on the incident surface of the ZnTe crystal, and then sequentially passes through the ZnTe crystal, the quarter wave plate and the Wollaston prism and is detected by a photoelectric balance detector; the photoelectric balance detector is connected with the computer through the phase-locked amplifier.
In a preferred embodiment of the present invention, identical dielectric cylinders in a 4×4 array are selected, and the distances between adjacent dielectric cylinders are equal, specifically, the radius of the selected dielectric cylinder is 5 microns, the height is 1 micron, and the distance between adjacent dielectric cylinders is 5 microns.
In a preferred embodiment of the present invention, the dielectric material of the dielectric cylinder 25 is lithium tantalate having a high dielectric constant.
In a preferred embodiment of the present invention, the substrate material is dielectric silicon.
The alcohol concentration is detected by using the high-sensitivity terahertz spectrum sensing detection device for liquid concentration, which is described in the embodiment, and the steps are as follows:
1) Adding an alcohol solution to be detected into the terahertz metamaterial array structure until the cavity for storing the liquid to be detected is fully filled;
2) Laser generated by the femtosecond laser passes through a chopper and a beam splitter, and the beam splitter divides the laser generated by the femtosecond laser into pump light and detection light; the pump light excites terahertz pulses through a photoconductive antenna, the terahertz pulses sequentially pass through a first parabolic mirror for collimation and a first polytetrafluoroethylene lens for focusing and then reach an incident spherical surface of the first silicon lens, the terahertz pulses pass through a polyethylene cover plate through the coupling of the first silicon lens, enter a cavity for storing liquid to be detected, enter an incident plane of a second silicon lens through a silicon substrate, are coupled and emergent from an emergent spherical surface of the second silicon lens, and the emergent terahertz pulses sequentially pass through the second polytetrafluoroethylene lens for collimation and the second parabolic mirror for focusing and then reach an incident surface of a ZnTe crystal through a thin film beam splitter; the detection light sequentially passes through the delay line, the first reflecting mirror, the second reflecting mirror and the thin film beam splitter, is converged with terahertz pulses on the incident surface of the ZnTe crystal, and then sequentially passes through the ZnTe crystal, the quarter wave plate and the Wollaston prism to be detected by the photoelectric balance detector; the measured electrical signals are amplified by a phase-locked amplifier and then sent to a computer, and the data information of the transmittance measured by a terahertz time-domain spectroscopy system is fitted by the computer, so that the terahertz transmission spectrum of the detected alcohol solution is finally obtained;
3) The frequency corresponding to the lowest transmittance point in the terahertz transmission spectrum of the alcohol solution is taken as the resonance frequency point of the alcohol, the positions of the resonance frequency point of the alcohol and the concentration of the alcohol solution are in one-to-one correspondence, as shown in fig. 4, the terahertz transmission spectrum of the alcohol solution with the concentration ranging from 0% to 100% in the alcohol concentration calibration is shown, the terahertz transmission spectrums of the alcohol solution with the same concentration at different frequencies are different, the terahertz transmission spectrums of the alcohol solutions with different concentrations have obvious differences, the calibration curve between the resonance frequency point of the alcohol solution and the concentration of the alcohol can be obtained according to the curve shown in fig. 4, and then the concentration of the alcohol solution to be measured is further obtained according to the calibration curve of the resonance frequency point and the concentration of the alcohol.
The above is only a preferred example of the present invention and is not intended to limit the present invention. Any modifications, substitutions, etc. which are within the spirit and principles of the present invention will be apparent to those skilled in the art and are intended to be within the scope of the present invention.
Claims (2)
1. The high-sensitivity terahertz spectrum detection device for the liquid concentration is characterized by comprising a femtosecond laser (1), a chopper (2), a beam splitter (3), a photoconductive antenna (4), a first parabolic mirror (5), a first polytetrafluoroethylene lens (6), a first silicon lens (7), a terahertz metamaterial array structure (8), a second silicon lens (9), a second polytetrafluoroethylene lens (10), a second parabolic mirror (11), a delay line (12), a first reflecting mirror (13), a second reflecting mirror (14), a thin film beam splitter (15), a ZnTe crystal (16), a quarter wave plate (17), a Wollaston prism (18), a photoelectric balance detector (19), a phase-locked amplifier (20) and a computer (21); the terahertz metamaterial array structure (8) comprises a silicon substrate (23), a medium cylinder (25), a polyethylene cover plate (22) and a polyethylene sealing baffle (27); the medium cylinders are arranged between the polyethylene cover plate and the silicon substrate, two end faces of the medium cylinders are respectively abutted against the polyethylene cover plate and the silicon substrate, and a plurality of medium cylinders are in a periodic array structure; a cavity (26) for storing liquid to be tested is arranged between the polyethylene cover plate and the silicon substrate and around the medium cylinder, and the cavity is sealed by a polyethylene sealing baffle between the polyethylene cover plate and the silicon substrate;
a chopper (2) and a beam splitter (3) are sequentially arranged on a laser path generated by the femtosecond laser (1), and the beam splitter (3) divides laser generated by the femtosecond laser (1) into pump light and detection light; the pump light is provided with a photoconductive antenna (4), terahertz pulses are excited by the photoconductive antenna (4), the terahertz pulses sequentially pass through a first parabolic mirror (5) for collimation and a first polytetrafluoroethylene lens (6) for focusing and then reach an incident spherical surface of the first silicon lens (7), the terahertz pulses pass through a polyethylene cover plate through the coupling of the first silicon lens, enter a cavity for storing liquid to be detected, enter an incident plane of a second silicon lens (9) through a silicon substrate, are coupled and emergent from an emergent spherical surface of the second silicon lens (9), and the emergent terahertz pulses pass through a film beam splitter (15) for reaching an incident surface of a ZnTe crystal (16) after being collimated by the second polytetrafluoroethylene lens (10) and focused by the second parabolic mirror (11); a delay line (12), a first reflecting mirror (13), a second reflecting mirror (14) and a thin film beam splitter (15) are sequentially arranged on the detection light path; after being reflected by a thin film beam splitter, the detection light is converged with terahertz pulses on the incident surface of the ZnTe crystal, and then sequentially passes through the ZnTe crystal, a quarter wave plate (17) and a Wollaston prism (18) and is detected by a photoelectric balance detector (19); the photoelectric balance detector is connected with a computer (21) through a lock-in amplifier (20);
the medium cylinders are identical, and the distances between the adjacent medium cylinders are equal; the medium material of the medium cylinder (25) is lithium tantalate;
the radius of the medium cylinder is 4-6 microns, the height is 1-2 microns, and the distance between adjacent medium cylinders is 5-7 microns.
2. A detection method of the high sensitivity terahertz spectrum detection apparatus for liquid concentration according to claim 1, characterized by the steps of:
1) Adding liquid to be detected into the terahertz metamaterial array structure until the cavity for storing the liquid to be detected is fully filled;
2) Laser generated by the femtosecond laser passes through a chopper and a beam splitter, and the beam splitter divides the laser generated by the femtosecond laser into pump light and detection light; the pump light excites terahertz pulses through a photoconductive antenna, the terahertz pulses sequentially pass through a first parabolic mirror for collimation and a first polytetrafluoroethylene lens for focusing and then reach an incident spherical surface of the first silicon lens, the terahertz pulses pass through a polyethylene cover plate through the coupling of the first silicon lens, enter a cavity for storing liquid to be detected, enter an incident plane of a second silicon lens through a silicon substrate, are coupled and emergent from an emergent spherical surface of the second silicon lens, and the emergent terahertz pulses sequentially pass through the second polytetrafluoroethylene lens for collimation and the second parabolic mirror for focusing and then reach an incident surface of a ZnTe crystal through a thin film beam splitter; the detection light sequentially passes through the delay line, the first reflecting mirror, the second reflecting mirror and the thin film beam splitter, is converged with terahertz pulses on the incident surface of the ZnTe crystal, and then sequentially passes through the ZnTe crystal, the quarter wave plate and the Wollaston prism to be detected by the photoelectric balance detector; the measured electrical signals are amplified by a phase-locked amplifier and then sent to a computer, and the measured transmittance data information is subjected to fitting processing by the computer to obtain a terahertz transmission spectrum of the liquid to be measured;
3) And taking the frequency corresponding to the point with the lowest transmittance in the terahertz transmission spectrum of the liquid to be measured as a resonance frequency point, and obtaining the concentration of the liquid to be measured according to a calibration curve between the resonance frequency point of the liquid to be measured and the concentration of the liquid to be measured.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910554917.9A CN110132886B (en) | 2019-06-25 | 2019-06-25 | High-sensitivity terahertz spectrum detection device and method for liquid concentration |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910554917.9A CN110132886B (en) | 2019-06-25 | 2019-06-25 | High-sensitivity terahertz spectrum detection device and method for liquid concentration |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110132886A CN110132886A (en) | 2019-08-16 |
| CN110132886B true CN110132886B (en) | 2023-09-26 |
Family
ID=67579495
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910554917.9A Active CN110132886B (en) | 2019-06-25 | 2019-06-25 | High-sensitivity terahertz spectrum detection device and method for liquid concentration |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110132886B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114279998B (en) * | 2021-12-29 | 2024-01-09 | 福州大学 | Liquid enhancement sensing system and method based on quasi-Chinese character 'Hui' type terahertz metamaterial |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106442424A (en) * | 2016-12-08 | 2017-02-22 | 中国计量大学 | Alcohol concentration measuring device utilizing graphene terahertz surface plasma effect and method thereof |
| CN206804521U (en) * | 2016-12-08 | 2017-12-26 | 中国计量大学 | Utilize the alcohol concentration measurement apparatus of graphene Terahertz surface plasma effect |
| CN108020525A (en) * | 2018-01-11 | 2018-05-11 | 中国计量大学 | A kind of hazardous gas high sensitivity Terahertz spectrum detection device and method |
| CN207730658U (en) * | 2018-01-11 | 2018-08-14 | 中国计量大学 | A kind of hazardous gas high sensitivity Terahertz spectrum detection device |
-
2019
- 2019-06-25 CN CN201910554917.9A patent/CN110132886B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106442424A (en) * | 2016-12-08 | 2017-02-22 | 中国计量大学 | Alcohol concentration measuring device utilizing graphene terahertz surface plasma effect and method thereof |
| CN206804521U (en) * | 2016-12-08 | 2017-12-26 | 中国计量大学 | Utilize the alcohol concentration measurement apparatus of graphene Terahertz surface plasma effect |
| CN108020525A (en) * | 2018-01-11 | 2018-05-11 | 中国计量大学 | A kind of hazardous gas high sensitivity Terahertz spectrum detection device and method |
| CN207730658U (en) * | 2018-01-11 | 2018-08-14 | 中国计量大学 | A kind of hazardous gas high sensitivity Terahertz spectrum detection device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110132886A (en) | 2019-08-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6479822B1 (en) | System and Method for terahertz frequency measurements | |
| Theuer et al. | Terahertz time‐domain spectroscopy of gases, liquids, and solids | |
| CN2874476Y (en) | Terahertz time domain spectral instrument based on optical rectification | |
| CN106442424B (en) | Alcohol concentration measuring device and method using graphene terahertz surface plasma effect | |
| US6977379B2 (en) | T-ray Microscope | |
| CN106441580B (en) | The incident terahertz time-domain spectroscopy instrument for surveying transmission and reflection simultaneously of variable-angle | |
| CN105699317A (en) | Terahertz time-domain spectrograph capable of entering at fixed angle and simultaneously detecting transmission and reflection | |
| EP0577285A1 (en) | Surface plasmon resonance measuring instruments | |
| CN108020525B (en) | High-sensitivity terahertz spectrum detection device and method for dangerous gas | |
| CN102830069B (en) | Alcohol concentration measuring device by using terahertz anisotropic medium resonance effect and method thereof | |
| CN104964932B (en) | A kind of integral system and application for measuring Terahertz normal transmission spectrum and reflectance spectrum | |
| CN109030406B (en) | Terahertz frequency spectrum calibration system and method | |
| Dobroiu et al. | THz-wave spectroscopy applied to the detection of illicit drugs in mail | |
| CN206804521U (en) | Utilize the alcohol concentration measurement apparatus of graphene Terahertz surface plasma effect | |
| CN109142266B (en) | Terahertz fine spectrum detector | |
| CN111442733A (en) | Nondestructive testing method for rubber composite material based on terahertz time-domain spectral imaging | |
| CN102192884B (en) | Method for imaging of samples by using polarization controllable terahertz waves | |
| CN110132886B (en) | High-sensitivity terahertz spectrum detection device and method for liquid concentration | |
| CN207730658U (en) | A kind of hazardous gas high sensitivity Terahertz spectrum detection device | |
| CN101975754A (en) | Reflective terahertz spectral analysis method capable of eliminating phase error | |
| CN210487596U (en) | High-sensitivity terahertz spectrum detection device for liquid concentration | |
| CN207850914U (en) | A kind of detection device and detecting system based on THz wave | |
| CN105806800A (en) | Terahertz optical fiber sensing device and pollutant detection method using the same | |
| CN210376134U (en) | Terahertz-based indoor environmental pollutant detection device | |
| CN114152588A (en) | Self-reference optical parameter measuring method for reflective terahertz time-domain spectroscopy composite material |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |