CN101995379A - Magneto-optic detector for transparent solution concentration - Google Patents

Abstract

The invention relates to a magnet-optic detector for transparent solution concentration. The detector comprises a laser (1), a polarizer (2), a first transparent container (3) and a second transparent container (4), an alternating current magneto-optic modulator (6), an analyzer (7), a photoelectric detector (8), a signal conditioner (9) and a microcomputer process and display unit (10) which are connected in sequence, wherein a magnetostatic field (5) is arranged beside the first transparent container (3) and the second transparent container (4); the light beam emitted by the laser (1) passes through the polarizer (2), the first transparent container (3) and the second transparent container (4), the alternating current magneto-optic modulator (6) and the analyzer (7) and then reaches the photoelectric detector (8); the photoelectric detector (8) collects a light intensity signal and converts the light intensity signal into light intensity electrical signal to be output to the signal conditioner (9); the signal conditioner (9) separates the direct current component and frequency doubling component in the light intensity electrical signal output by the photoelectric detector (8); and the separated direct current component and frequency doubling component respectively enter the microcomputer process and display unit (10).

Description

Clear solution concentration magneto-optic pick-up unit

Technical field

The present invention relates to a kind of clear solution concentration magneto-optic pick-up unit and principle of work thereof, belong to the technical field of Photoelectric Detection, photoelectric sensing and optical information processing.

Background technology

Magnetic is one of basic physical attribute of material, changes by some parameter that can understand material to the detection research of changing of magnetism, such as the solution of concentration information can understand to(for) the detection of the solution magnetic rotation optic angle that contains the paramagnetic solute.Magnetooptics is an ancient and unfailing subject, and it in the application in optical detection and photoelectric sensing field more and more widely; Wherein using maximum is faraday's magnetic rotation effect, comprises that current sensor, magnetic field sensor, magneto optic isolator, magneto-optic circulators etc. spread all over a plurality of optical fields such as light detection, light sensing, optical communication.

At industrial circles such as chemical industry, food and health cares, usually need the concentration of solution is detected, the concentration of solution physical quantitys many with it are correlate all, therefore as proportion, conductivity, refractive index, the velocity of sound, optical activity, Verdet constant etc., can characterize the variation of solution concentration in principle with the variation of a certain physical quantity wherein.At present more deep for the detection method research of solution concentration, precision also reaches certain requirement; But utilize the research of magneto-optic technology for detection solution concentration less, and general detection method do not solve the detection problem of mixed solution concentration, existing partially mixed solution concentration detection technique device is complicated ^[1], and generally adopt the detection method of intrusive mood easily solution to be polluted.Patent of the present invention proposes the method for separation detection solute Verdet constant based on the Faraday magnetooptical effect principle, and the solution concentration that contains paramagnetism or diamagnetism solute is detected.This detection technique can be used for detecting the clear solution concentration that contains the single component solute or contain multiple paramagnetism or the concentration of the various solutes of transparent mixed solution of diamagnetism solute.This method directly obtains the Verdet constant of solute and the calibration relation between the concentration by the Verdet constant of separation detection solute, has eliminated the influence of background optically-actives such as solvent and container, in conjunction with the dispersion characteristics of paramagnetism or diamagnetism solute Verdet constant ^[2], can also be used to detect multiple solute mixed solution concentration; The signal processing technology that adopts magneto-optic to modulate has improved the detection sensitivity of system; The method that the employing two paths of signals is divided by has been eliminated the influence of light source luminescent power instability and light intensity absorption factor; Adopt non-contacting detection method, pollution-free to solution; This technology will obtain to use preferably at the solution concentration detection range.

List of references

[1] Sun Xuan, Xu Kexin, Ai Changsheng etc. based on the milk constituents concentration detection technique [J] of multi-component liquid concentration sensor. sensing technology journal, 2006,19 (4): 966～969

[2] Liu Gongqiang, happy will is strong, Shen Defang etc. magnetooptics [M]. and Shanghai: Shanghai science tech publishing house, 2001:42～44

[3] Ceng Aijun, Wang Xiangchao, Dong does people etc. the application [J] of light ball modulator in the modulation of polarization direction. Chinese laser, 2005,32 (8): 1063～1066

[4] Li Chengren, Lv Ling etc. DETERMINE CONCENTRATION OF LIQUID BY FARADAY EFFECT [J]. Liaoning Normal University's journal (natural science edition), 1996,19 (3): 259～262

Summary of the invention

Technical matters: the objective of the invention is to propose a kind of clear solution concentration magneto-optic pick-up unit, solve the problem that influences of utilizing magneto-optic technology background magnetic rotation of existence in strength of fluid detects based on the solute Verdet constant separation detection.While, the concentration that proposes to utilize the magneto-optic technology to solve mixed solution detected problem in conjunction with the dispersion characteristics of the Verdet constant of paramagnetism or diamagnetism solute.

Technical scheme: clear solution concentration magneto-optic pick-up unit of the present invention comprises tactic laser instrument, the polarizer, first transparent vessel and second transparent vessel, AC magnetism photomodulator, analyzer, photodetector, signal conditioner and MICROCOMPUTER PROCESSING and display unit, and static magnetic field is positioned at by first transparent vessel and second transparent vessel; Send light beam by laser instrument and arrive photodetector through the polarizer, first transparent vessel and second transparent vessel, AC magnetism photomodulator, analyzer in proper order, be converted to the light intensity electric signal by photodetector collection light intensity signal and output to signal conditioner, signal conditioner separates DC component in the light intensity electric signal of photodetector output with two frequency multiplication components, DC component after the separation and two frequency multiplication components are input to the MICROCOMPUTER PROCESSING display unit respectively.

Described first transparent vessel and second transparent vessel adopt identical transparent vessel, deposit clear solution in first transparent vessel, deposit transparent solvent in second transparent vessel.

Described first transparent vessel static magnetic field other that be positioned at being positioned at second transparent vessel, magnitude of field intensity equates that direction is opposite, the magnetic line of force is parallel with light.

The described analyzer and the polarizer direction of shaking thoroughly places orthogonal position.

A kind of clear solution concentration magneto-optic detection technique device of the present invention as shown in Figure 1.Laser instrument adopts LASER Light Source among the figure, the laser that sends is incident to first transparent vessel and second transparent vessel after becoming linearly polarized light through the polarizer, first transparent vessel is deposited solution to be measured, second transparent vessel is deposited solvent, first transparent vessel and second transparent vessel place respectively in the middle of left and right sides two parts of static magnetic field, two parts magnetic field, left and right sides equal and opposite in direction, direction is opposite, the magnetic line of force is parallel with incident ray, the magnetic rotation angle that produces in first transparent vessel is a solute, solvent and container three sum, the magnetic rotation angle that produces in second transparent vessel are solvent and container sum.Because first transparent vessel and second transparent vessel place equal and opposite in direction, magnetic field that direction is opposite respectively, according to the magneto-optic effect relative theory, the magnetic rotation optic angle that container and solvent produced in first transparent vessel and second transparent vessel is cancelled each other, therefore the linearly polarized light of incident through first transparent vessel and second transparent vessel after total magnetic rotation angle produce by solute in first transparent vessel, reach the purpose of solute magnetic rotation optic angle in the separation detection solution, and then obtain the Verdet constant of solute.

The magnetic rotation angle of having carried solute through the linearly polarized light behind second transparent vessel reenters and is incident upon the AC magnetism photomodulator, receive by photodetector by the light intensity behind the analyzer, photodetector inputs to signal conditioner with the light intensity signal that obtains, and signal conditioner is isolated DC component and the two frequency multiplication components in the light intensity signal ^[3], be input to MICROCOMPUTER PROCESSING and display unit respectively, the magnetic rotation angle that microcomputer is compared DC component can calculate solute with the effective value of two frequency multiplication components.

Pass to ac signal i=i to magneto-optic modulator ₀Sin ω t, thus alternating magnetic field H=H produced ₀Sin ω t, the alternation magnetic rotation angle of generation is δ=δ ₀Sin ω t.If the magnetic rotation angle that solute produced is θ, then total magnetic rotation angle is (θ+δ ₀Sin ω t), the initial incident intensity of establishing through the polarizer is I ₀, consider (θ+δ ₀Sin ω t) less, then the light intensity by analyzer is:

$I=I_0{\sin }^2(\mathrm{\&theta;}+\mathrm{\&delta;})\&ap;I_0({\mathrm{\&theta;}}^2+\frac{{\mathrm{\&delta;}}_0^2}{2}+2\mathrm{\&theta;}{\mathrm{\&delta;}}_0\sin \mathrm{\&omega;t}-\frac{{\mathrm{\&delta;}}_0^2}{2}\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HSA00000301011600011.png"\; state="\{\{state\}\}">cos</figure-callout>}2\mathrm{\&omega;t})---\left(1\right)$

Wherein,

Be DC component, 2 θ δ ₀Sin ω t is a fundamental component, Be two frequency multiplication components, for the absorption factor etc. of eliminating the influence that light source luminescent power instability brought and eliminating light.The effective value of DC component and frequency multiplication component compared obtains (not considering circuit gain) relative light intensity value:

$I^{\&prime;}=\frac{{\mathrm{\&theta;}}^2+\frac{{{\mathrm{\&delta;}}_0}^2}{2}}{\frac{{{\mathrm{\&delta;}}_0}^2}{2\sqrt{2}}}=\sqrt{2}+\frac{2\sqrt{2}{\mathrm{\&theta;}}^2}{{{\mathrm{\&delta;}}_0}^2}---\left(2\right)$

The δ here ₀Be modulation angular width degree, be considered as given value, relative light intensity value I ' can directly be calculated by computing machine, just can draw the size of θ like this according to formula (2), thereby separation detection goes out the magnetic rotation angle θ of solute.According to Faraday magnetooptical effect, θ=VHL, V are Verdet constant again, and H is a magnetic field intensity, and L is the length that light is propagated in sample, and H and L all can be by measuring, thereby calculate the Verdet constant V of solute.

For the clear solution that only contains a kind of paramagnetism or diamagnetism solute, can dispose the solution to be measured of several normal concentrations, the Verdet constant of solute during respectively by native system separation detection variable concentrations, again by data fitting obtain between solute Verdet constant and the concentration calibration relation (be generally: V (c, λ, T)=ck (λ, T), wherein c, λ, T are respectively the concentration of solute, the light wavelength and the environment temperature of use), (λ T) is calibration coefficient to k ^[4]When this solute was dissolved in different solvents, this calibration relation was still set up; Therefore no matter this solute is dissolved in any solvent, as long as utilize this detection system that the Verdet constant of solute is carried out separation detection, the Verdet constant and the existing calibration relation of the solute that obtains compared, can obtain the concentration of solution.If in conjunction with the dispersion characteristics of paramagnetism and diamagnetism solute Verdet constant, use the incident light of different wave length, can also detect the transparent mixed solution concentration that contains multiple composition solute.

To formula (2) differentiate, can draw system's detection sensitivity formula:

$S=\frac{4\sqrt{2}\mathrm{\&theta;}}{{{\mathrm{\&delta;}}_0}^2}---\left(3\right)$

This shows modulation angular width degree δ ₀More little, detection sensitivity is high more.

Beneficial effect: according to above narration as can be known, the present invention has following characteristics:

The present invention utilizes the magneto-optic effect principle, designed solution concentration detection technique, the multiple composition solute mixed solution concentration that this technology can be used to detect the solution concentration of single component solute and contain paramagnetism or diamagnetism solute based on the solute Verdet constant separation detection.This method adopts the separation detection technology to eliminate the influence of background optically-actives such as solvent and container; The signal processing technology that adopts magneto-optic to modulate has improved the detection sensitivity of system; The method that the employing two paths of signals is divided by has been eliminated the influence of factors such as light source luminescent power instability and light intensity absorption; Adopt non-contacting detection method, pollution-free to solution; This technology will obtain to use preferably at the solution concentration detection range.

The innovation part is: the present invention utilizes the magneto-optic effect principle, designed solution concentration detection technique, the multiple composition solute mixed solution concentration that this technology can be used to detect the solution concentration of single component solute and contain paramagnetism or diamagnetism solute based on the solute Verdet constant separation detection.Adopt the separation detection technology to eliminate the influence of background optically-actives such as solvent and container; The method that the employing two paths of signals is divided by has been eliminated the influence of factors such as light source luminescent power instability and light intensity absorption; Adopt non-contacting detection method, pollution-free to solution; This technology will obtain to use preferably at the solution concentration detection range.

Description of drawings

Fig. 1 is a kind of clear solution concentration magneto-optic pick-up unit synoptic diagram.

Have among the figure: laser instrument 1, the polarizer 2, first transparent vessel 3, second transparent vessel 4, static magnetic field 5, AC magnetism photomodulator 6, analyzer 7, photodetector 8, signal conditioner 9, MICROCOMPUTER PROCESSING and display unit 10.

Embodiment

Specific embodiment 1:

The present invention proposes a kind of clear solution concentration magneto-optic and detects this pick-up unit and comprise tactic laser instrument 1, the polarizer 2, first transparent vessel 3 and second transparent vessel 4, AC magnetism photomodulator 6, analyzer 7, photodetector 8, signal conditioner 9 and MICROCOMPUTER PROCESSING and display unit 10, and static magnetic field 5 is positioned at first transparent vessel 3 and second transparent vessel 4 is other; Send light beam by laser instrument 1 and arrive photodetector 8 through the polarizer 2, first transparent vessel 3 and second transparent vessel 4, AC magnetism photomodulator 6, analyzer 7 in proper order, be converted to the light intensity electric signal by photodetector 8 collection light intensity signals and output to signal conditioner 9, signal conditioner 9 separates DC component in the light intensity electric signal of photodetector 8 outputs with two frequency multiplication components, DC component after the separation and two frequency multiplication components are input to MICROCOMPUTER PROCESSING display unit 10 respectively.

The magnetic line of force is parallel with incident ray, passes to alternating current i=i for the AC magnetism photomodulator ₀Sin ω t, thus an alternation magnetic rotation angle δ=δ produced ₀Sin ω t.The laser that laser instrument 1 sends is incident to the polarizer 2, container first transparent vessel 3 and second transparent vessel 4, AC magnetism photomodulator 6, analyzer 7, photodetector 8 successively.If the magnetic rotation angle that solute produced is θ, the initial incident intensity of the process polarizer 2 is I ₀, then can draw the size of θ, thereby separation detection goes out the magnetic rotation angle θ of solute by formula (2).According to Faraday magnetooptical effect, θ=VHL, V are Verdet constant again, and H is a magnetic field intensity, and L is the sample light path, and H and L all can be by measuring, thereby calculate the Verdet constant V of solute.

For the clear solution that only contains a kind of paramagnetism or diamagnetism solute, can dispose the solution to be measured of several normal concentrations, the Verdet constant of solute during respectively by native system separation detection variable concentrations, again by data fitting obtain between solute Verdet constant and the concentration calibration relation (be generally: V (c, λ, T)=ck (λ, T), wherein c, λ, T are respectively the concentration of solute, the light wavelength and the environment temperature of use), (λ T) is calibration coefficient to k.When this solute was dissolved in different solvents, this calibration relation was still set up; Therefore no matter this solute is dissolved in any solvent, as long as utilize this detection system that the Verdet constant of solute is carried out separation detection, the Verdet constant and the existing calibration relation of the solute that obtains compared, can obtain the concentration of solution.

Specific embodiment 2:

The present invention proposes a kind of clear solution concentration magneto-optic detection technique.Pick-up unit is made up of laser instrument 1, the polarizer 2, first transparent vessel 3, second transparent vessel 4, static magnetic field 5, AC magnetism photomodulator 6, analyzer 7, photodetector 8, signal conditioner 9 and MICROCOMPUTER PROCESSING and display unit 10.

Deposit solution in first transparent vessel 3, deposit solvent in second transparent vessel 4, first transparent vessel 3 places equal and opposite in direction, magnetic field that direction is opposite respectively, makes the magnetic line of force parallel with incident ray.Pass to alternating current i=i for the AC magnetism photomodulator ₀Sin ω t, thus an alternation magnetic rotation angle δ=δ produced ₀Sin ω t.The laser that laser instrument 1 sends is incident to the polarizer 2, first transparent vessel 3, second transparent vessel 4, AC magnetism photomodulator 6, analyzer 7, photodetector 8 successively.If the magnetic rotation angle that solute produced is θ, the initial incident intensity of the process polarizer 2 is I ₀, then can draw the size of θ, thereby separation detection goes out the magnetic rotation angle θ of solute by formula (2).According to Faraday magnetooptical effect, θ=VHL, V are Verdet constant again, and H is a magnetic field intensity, and L is the sample light path, and H and L all can be by measuring, thereby calculate the Verdet constant V of solute.

For the transparent mixed solution that contains two kinds of paramagnetisms or diamagnetism solute A and B, use the incident light of λ 1 and 2 two kinds of different wave lengths of λ, for the Verdet constant of solute A and the calibration relation between the concentration can by calibration test (calibrating method is with embodiment 1) obtain into:

V _Aλ1＝k _Ac _A

(4)

V _Aλ2＝k′ _Ac _A

K wherein _A, k ' _ABe calibration coefficient, c _AConcentration for the A solute.

For the Verdet constant of solute B and the calibration relation between the concentration can by the calibration experiment obtain into:

V _Bλ1＝k _Bc _B

(5)

V _Bλ2＝k′ _Bc _B

Wherein, k _B, k ' _BBe calibration coefficient, c _BConcentration for the B solute.

Corresponding incident wavelength λ 1, the total Verdet constant of two kinds of solutes of A, B is:

V _{Total λ 1}=V _{A λ 1}± V _{B λ 1}=k _Ac _A± k _Bc _B(6)

"+,-" number represents respectively that A, two kinds of solute magnetic rotations of B direction are identical or opposite in the formula.

Corresponding incident wavelength λ 2, the total Verdet constant of two kinds of solutes of A, B is:

V _{Total λ 2}=V _{A λ 2}± V _{B λ 2}=k ' _Ac _A± k ' _Bc _B(7)

"+,-" number represents respectively that A, two kinds of solute magnetic rotations of B direction are identical or opposite in the formula.

Form the linear equation in two unknowns group by formula (6) and formula (7), wherein, A, B two kinds of solute magnetic rotations direction and k _A, k ' _A, k _B, k ' _BAll can be considered known, separate this system of equations, just can draw the concentration c of solute A and solute B _AAnd c _B

Specific embodiment 3:

The present invention proposes a kind of clear solution concentration magneto-optic detection technique.Pick-up unit is made up of laser instrument 1, the polarizer 2, transparent vessel first transparent vessel 3, second transparent vessel 4, static magnetic field 5, AC magnetism photomodulator 6, analyzer 7, photodetector 8, signal conditioner 9 and MICROCOMPUTER PROCESSING and display unit 10.

Deposit solution in first transparent vessel 3, deposit solvent in second transparent vessel 4, first transparent vessel 3, second transparent vessel 4 place equal and opposite in direction, magnetic field that direction is opposite respectively, make the magnetic line of force parallel with incident ray.Pass to alternating current i=i for the AC magnetism photomodulator ₀Sin ω t, thus an alternation magnetic rotation angle δ=δ produced ₀Sin ω t.The laser that laser instrument 1 sends is incident to the polarizer 2, first transparent vessel 3, second transparent vessel 4, AC magnetism photomodulator 6, analyzer 7, photodetector 8 successively.If the magnetic rotation angle that solute produced is θ, the initial incident intensity of the process polarizer 2 is I ₀, then can draw the size of θ, thereby separation detection goes out the magnetic rotation angle θ of solute by formula (2).According to Faraday magnetooptical effect, θ=VHL, V are Verdet constant again, and H is a magnetic field intensity, and L is the sample light path, and H and L all can be by measuring, thereby calculate the Verdet constant V of solute.

If contain n kind diamagnetism or paramagnetism solute in the solution, the concentration of establishing n kind solute is c _n, then its Verdet constant can be expressed as V _n(c _n, λ _m, T)=c _nK _n(λ _m, T), c wherein _n, λ _m, T is respectively the concentration of n kind solute, the light wavelength and the environment temperature of use.k _n(λ _m, be calibration coefficient (calibrating method is with embodiment 1) T), be considered as known.When total Verdet constant of the n kind solute that measures by native system with the light of m kind different wave length can be expressed as:

When m=n, (8) formula is a n unit linear function group, finds the solution the concentration c that can obtain every kind of solute _n"-" number represents the situation that certain solute magnetic rotation direction is opposite with other solute in the formula.

Claims (4)

1. clear solution concentration magneto-optic pick-up unit, it is characterized in that this pick-up unit comprises tactic laser instrument (1), the polarizer (2), first transparent vessel (3) and second transparent vessel (4), AC magnetism photomodulator (6), analyzer (7), photodetector (8), signal conditioner device (9) and MICROCOMPUTER PROCESSING and display unit (10), static magnetic field (5) is positioned at first transparent vessel (3) and second transparent vessel (4) is other; Send light beam by laser instrument (1) and pass through the polarizer (2), first transparent vessel (3) and second transparent vessel (4), AC magnetism photomodulator (6), analyzer (7) arrival photodetector (8) in proper order, be converted to the light intensity electric signal by photodetector (8) collection light intensity signal and output to signal conditioner device (9), signal conditioner (9) separates DC component in the light intensity electric signal of photodetector (8) output with two frequency multiplication components, DC component after the separation and two frequency multiplication components are input to MICROCOMPUTER PROCESSING display unit (10) respectively.

2. clear solution concentration magneto-optic pick-up unit according to claim 1, it is characterized in that described first transparent vessel (3) and second transparent vessel (4) adopt identical transparent vessel, first transparent vessel is deposited clear solution in (3), and second transparent vessel is deposited transparent solvent in (4).

3. clear solution concentration magneto-optic pick-up unit according to claim 1, it is characterized in that described first transparent vessel (3) static magnetic field (5) other that be positioned at being positioned at second transparent vessel (4), magnitude of field intensity equates that direction is opposite, and the magnetic line of force is parallel with light.

4. clear solution concentration magneto-optic pick-up unit according to claim 1 is characterized in that the described analyzer (7) and the polarizer (2) direction of shaking thoroughly places orthogonal position.

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