CN105466887B - The detecting system and method for thin-walled closed glass chamber optical parameter - Google Patents
The detecting system and method for thin-walled closed glass chamber optical parameter Download PDFInfo
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- CN105466887B CN105466887B CN201510824142.4A CN201510824142A CN105466887B CN 105466887 B CN105466887 B CN 105466887B CN 201510824142 A CN201510824142 A CN 201510824142A CN 105466887 B CN105466887 B CN 105466887B
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- G—PHYSICS
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- 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
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
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Abstract
The invention discloses a kind of detecting systems of thin-walled closed glass chamber optical parameter, including light source, lock-in amplifier, optical chopper, photodetector, light splitting piece, lens, diaphragm and computer；Light source generates laser and enters main optical path, adjusts spot size through two lens, then through diaphragm shaping hot spot, control light intensity；Input light forms reference path and optical path through light splitting piece, and the laser of optical path passes through the surface of chamber, is reflected into photodetector, and output signal is modulated through lock-in amplifier, connects computer；The laser of reference path is directly detected by photodetector, and output signal is modulated through another lock-in amplifier, connects computer.The present invention also proposes a kind of corresponding detection method.The present invention solves the problems, such as thin-walled closed glass chamber optical parameter (physics wall thickness, refractive index) non-destructive testing, provides the foundation for ultra-high sensitive inertia and the subsequent further investigation of magnetic field measuring device.
Description
Technical field
The invention belongs to spectrum analysis and laser measuring technique field, especially a kind of ultra-high sensitive inertia and magnetic-field measurement
The detecting system and method for device sensitivity gauge outfit (thin-walled closed glass chamber) optical parameter.
Background technology
Based on SERF effect atomic spin inertia and magnetic field measuring device, the angular motion flow characteristic of atom and the drawing of atom are utilized
More carries out inertia and magnetic-field measurement into dynamic characteristic, and measurement sensitivity is far above conventional apparatus.Ultra-high sensitive inertia is surveyed with magnetic field
Measure device, can serve chemical composition and structural analysis and biomolecular structure analysis, atomic spin gyroscope magnetometer
Equal fields.The thin-walled closed glass chamber of interior alkali metal containing and inert gas is the quick of ultra-high sensitive magnetic field and inertial measuring unit
Feel gauge outfit, the performance of chamber inherently determines the limit of instrumental sensitivity.Therefore, to thin-walled closed glass chamber itself light
The research for learning parameter, is ultra-high sensitive inertia and the essential part of magnetic field measuring device.
Currently, for thin-walled closed glass chamber own optical parameter detection mainly by destructive test, by chamber
It breaks into pieces, using its thickness of vernier caliper measurement, additionally by the refractive index of chemical experiment detection chambers material；This method is simple
It is easy, but permanent damage can be caused to chamber, it can not restore.
Invention content
Goal of the invention：For problems of the prior art, the present invention provides a kind of thin-walled closed glass chamber optical
The detecting system of parameter realizes the non-destructive testing to chamber, and further provides for a kind of method that can realize above system.
Technical solution：The present invention proposes a kind of detecting system of thin-walled closed glass chamber optical parameter, including：For producing
The light source of raw input light, is used for lock-in amplifier, optical chopper and the photodetector of modulating and demodulating signal, is used for light path tune
Component light splitting piece, lens, diaphragm and the computer of section；
Light source generates laser and enters main optical path, adjusts spot size through two lens, then through diaphragm shaping hot spot, control light
By force；Input light forms reference path and optical path after light splitting piece, and the laser of optical path passes through the surface of chamber, reflection
Into photodetector, output signal connects computer after lock-in amplifier is modulated；The laser of reference path is directly by light
Electric explorer detects, and output signal connects computer after the modulation of another lock-in amplifier.
The present invention also proposes a kind of detection method of thin-walled closed glass chamber optical parameter, includes the following steps：
1) laser used in experiment is demarcated；
2) the control temperature for changing laser adjusts the frequency of laser, and records initial data by related experiment equipment,
Amplitude and frequency, the amplitude of modulated signal including measuring signal and frequency；
3) square-wave frequency modulation is carried out to measured signal, the frequency of optical chopper is set, such as formula (1)；And utilize orthogonal two
Road signal demodulates measured signal, such as formula (3) and formula (4)；According to the principle that Multi-channel crossed is modulated, modulated signal and letter to be measured
It number is interacted by phase sensitivity sensor, such as formula (5) and formula (6)；It, which is exported, passes through after low-pass filter, most of high-frequency signal
It is removed, such as formula (7) and formula (8)；Two-way demodulated signal passes through vector summer, output signal Uout, such as formula (9)；
Sig (t)=Vr·Sq(ωt) (1)
In formula, Sig (t) indicates measured signal, VrIndicate that the amplitude of measured signal, Sq (ω t) indicate square-wave frequency modulation function,
ω indicates angular frequency；
Ref1(t)=Vicos(ωt+θ) (3)
Ref2(t)=Visin(ωt+θ) (4)
In formula, Ref1(t) modulated signal 1, Ref is indicated2(t) modulated signal 2 is indicated, it there are 90 ° of phases with modulated signal 1
Difference, ViIndicate that the amplitude of modulated signal, θ indicate the offset phase angle of modulated signal；
In formula,Indicate it is that measured signal and modulated signal 1 are modulated as a result,Indicate letter to be measured
Number with modulated signal 2 be modulated as a result, T indicate the time of integration, UoutIndicate the amplitude of measured signal；
4) step 3 is referred to, reflected light signal and incident optical signal are obtained, carries out related data fitting, obtains thin-walled closing
Glass chamber optical parameter, i.e. wall thickness and refractive index, specifically as shown in formula (10)：
In formula, IinIndicate the light intensity of incident laser, IRIndicate the light intensity of reflection laser, ItIndicate the light intensity of transmission laser, R0
Indicate that the reflectivity of measurement sample surfaces, λ indicate that the wavelength of laser, n indicate that the refractive index of sample to be tested, d expressions wait for test sample
The physical thickness of product, α indicate that the incidence angle of laser, β indicate the angle of emergence of laser.
Advantageous effect：It is proposed the inertia detected based on Multi-channel crossed and magnetic field measuring device sensitivity gauge outfit optical parameter
Detection method and system, the present invention solve thin-walled closed glass chamber optical parameter (physics wall thickness, refractive index) non-destructive testing
The problem of, it provides the foundation for ultra-high sensitive inertia and the subsequent further investigation of magnetic field measuring device.
Description of the drawings
Fig. 1 is the schematic diagram of detection method；
Reference numeral in figure is：Modulated signal 1, phaselocked loop 2, crystal oscillator 3, phase-modulator 4, phase sensitivity sensor 5, low pass filtered
Wave device 6, X are to DC component 7, vector summer 8, output signal 9, Y-direction DC component 10, operational amplifier 11, square-wave frequency modulation
Device 12, bandpass filter 13, measuring signal 14；
Fig. 2 is the system structure diagram of the present invention；
Reference numeral in figure is：Lock-in amplifier 15 measures sample 16, photodetector 17, light splitting piece 18, lens
19, optical chopper 20, diaphragm 21, lens 22, laser 23, computer 24；
Fig. 3 is the Distributed Feedback Laser calibration result figure of the embodiment of the present invention；
Fig. 4 is the experiment test original record figure of the embodiment of the present invention.
Specific implementation mode
In conjunction with Fig. 1 and Fig. 2 description present invention.
Fig. 1 be detection method schematic diagram, first analyze measuring signal 14 running route, measuring signal 14 into
Enter detecting system, by bandwidth filter 13, influence of the removal power frequency component to measurement, by square wave function 12 to measuring signal
It is modulated, by being interacted with modulated signal by phase sensitivity sensor after operational amplifier 11；Lower surface analysis reference
The running route of signal, after phaselocked loop 2 and internal crystal oscillator 3, phase and frequency information is accurately obtained reference signal 1,
Then a part of reference signal is directly interacted by phase sensitivity sensor 5 and measuring signal, and another part reference signal is passed through
Phase-modulator 4 occurs to interact by phase sensitivity sensor 5 and measuring signal after 90 ° of phase shifts；Two-way output signal 7 and 10 points
It Jing Guo not carry out vector sum operation by vector summer 8 and just obtain, what is needed is defeated after Butterworth low-pass filters 6
Go out signal 9.
Fig. 2 is the system structure diagram of the present invention, and laser is exported from light source 23, is adjusted by two lens 19 and 22
The size of hot spot carries out shaping to input light with diaphragm 21, controls the intensity of light；Input light is by light splitting piece 18 later by a branch of
Laser becomes two beam laser, and wherein beam of laser passes through the surface of chamber, is reflected into photodetector 17, photodetector
Output signal be connected to lock-in amplifier 15 and be modulated, output signal enters computer 24, and in addition beam of laser is directly used up
Electric explorer 17 is detected, and output signal is modulated by lock-in amplifier 15, finally enters computer 24.
The main optical path connects reference path and optical path through light splitting piece；Reference signal light path incident laser is visited by photoelectricity
Device detection is surveyed, lock-in amplifier modulates the output signal, finally connects computer；Measuring signal light path incident laser is through chamber table
Face is reflected into photodetector, and another lock-in amplifier modulates the output signal, finally connects computer.
Below with Cs simple substance closing thin-walled glass chamber (simple substance Cs, 600torr4He、50torrN2, rectangular gas chamber, the length of side
For 2.5cm).First, it is demarcated to testing Distributed Feedback Laser used, calibration result is as shown in Figure 3.
Second step, by changing the control temperature of laser, to adjust the frequency of laser；With 1 DEG C for step-size change laser
The temperature of device, and initial data is recorded by related experiment equipment, as shown in Figure 4.
Third walks, and carries out square-wave frequency modulation to measured signal, and the frequency that optical chopper is arranged is 65Hz, as shown in formula (1)；
And measured signal is demodulated using orthogonal two paths of signals, such as formula (3) and formula (4)；According to the principle that Multi-channel crossed is modulated, adjust
Signal processed is interacted with measured signal by phase sensitivity sensor, such as formula (5) and formula (6)；It, which is exported, passes through after low-pass filter,
Most of high-frequency signal is removed, such as formula (7) and formula (8)；Two-way demodulated signal passes through vector summer, output signal Uout, such as
Formula (9).
Sig (t)=Vr·Sq(ωt) (1)
In formula, Sig (t) indicates measured signal, VrIndicate that the amplitude of measured signal, Sq (ω t) indicate square-wave frequency modulation function,
ω indicates angular frequency.According to fourier series, formula (1) is expanded into following expression：
Ref1(t)=Vicos(ωt+θ) (3)
Ref2(t)=Visin(ωt+θ) (4)
In formula, Ref1(t) modulated signal 1 is indicated；Ref2(t) modulated signal 2 is indicated, it there are 90 ° of phases with modulated signal 1
Difference；ViIndicate that the amplitude of modulated signal, θ indicate the offset phase angle of modulated signal；
In formula,Indicate it is that measured signal and modulated signal 1 are modulated as a result,Indicate letter to be measured
Number with modulated signal 2 be modulated as a result, T indicate the time of integration, UoutIndicate the amplitude of measured signal.
4th step can accurately obtain reflected light signal I with reference to step 3RWith incident optical signal Iin, carry out related data
Fitting, can obtain thin-walled closed glass chamber optical parameter (physics wall thickness, refractive index), as shown in formula (10)：
In formula, λ indicates the wavelength of laser；N indicates the refractive index of sample to be tested；D indicates the physical thickness of sample to be tested；
α indicates the incidence angle of laser；β indicates the angle of emergence of laser；R0Indicate the reflectivity of measurement sample surfaces；IinIndicate incident laser
Light intensity；IRIndicate the light intensity of reflection laser；ItIndicate the light intensity of transmission laser.
The preferred embodiment of the present invention has been described above in detail, still, during present invention is not limited to the embodiments described above
Detail can carry out a variety of equivalents to technical scheme of the present invention within the scope of the technical concept of the present invention, this
A little equivalents all belong to the scope of protection of the present invention.
It is further to note that specific technical features described in the above specific embodiments, in not lance
In the case of shield, it can be combined by any suitable means.In order to avoid unnecessary repetition, the present invention to it is various can
The combination of energy no longer separately illustrates.
Claims (2)
1. a kind of detecting system of thin-walled closed glass chamber physics wall thickness and refractive index, including：Light for generating input light
Source is used for lock-in amplifier, optical chopper and the photodetector of modulating and demodulating signal, the component point for optical path adjusting
Mating plate, lens, diaphragm and computer；
Light source generates laser and enters main optical path, adjusts spot size through two lens, then through diaphragm shaping hot spot, control light intensity；
Input light forms reference path and optical path after light splitting piece, and the laser of optical path passes through the surface of chamber, is reflected into
In photodetector, output signal connects computer after lock-in amplifier is modulated；The laser of reference path is directly by photoelectricity
Detector detects, and output signal connects computer after the modulation of another lock-in amplifier.
2. a kind of thin-walled of the detecting system of thin-walled closed glass chamber physics wall thickness and refractive index using claim 1 is closed
The detection method of glass chamber physics wall thickness and refractive index, which is characterized in that include the following steps：
1) laser used in experiment is demarcated；
2) the control temperature for changing laser adjusts the frequency of laser, and records initial data by related experiment equipment, including
The amplitude and frequency of measuring signal, the amplitude of reference signal and frequency；
3) square-wave frequency modulation is carried out to measured signal, the frequency of optical chopper is set, such as formula (1)；And believed using orthogonal two-way
Number measured signal is demodulated, such as formula (3) and formula (4)；According to the principle that Multi-channel crossed is modulated, modulated signal is logical with measured signal
The interaction of phase sensitivity sensor is crossed, such as formula (5) and formula (6)；It is exported by after low-pass filter, most of high-frequency signal is gone
It removes, such as formula (7) and formula (8)；Two-way demodulated signal passes through vector summer, output signal Uout, such as formula (9)；
Sig (t)=Vr·Sq(ωt) (1)
In formula, Sig (t) indicates measured signal, VrIndicate that the amplitude of measured signal, Sq (ω t) indicate square-wave frequency modulation function, ω tables
Show angular frequency；
Ref1(t)=Vicos(ωt+θ) (3)
Ref2(t)=Visin(ωt+θ) (4)
In formula, Ref1(t) modulated signal 1, Ref is indicated2(t) modulated signal 2 is indicated, it has 90 ° of phase differences, V with modulated signal 1i
Indicate that the amplitude of modulated signal, θ indicate the offset phase angle of modulated signal；
In formula,Indicate it is that measured signal and modulated signal 1 are modulated as a result,Indicate letter to be measured
Number with modulated signal 2 be modulated as a result, T indicate the time of integration, UoutIndicate the amplitude of measured signal；
4) step 3 is referred to, reflected light signal and incident optical signal are obtained, related data fitting is carried out, obtains thin-walled closed glass
Chamber optical parameter, i.e. wall thickness and refractive index, specifically as shown in formula (10)：
In formula, IinIndicate the light intensity of incident laser, IRIndicate the light intensity of reflection laser, ItIndicate the light intensity of transmission laser, R0It indicates
The reflectivity of sample surfaces is measured, λ indicates that the wavelength of laser, n indicate that the refractive index of sample to be tested, d indicate sample to be tested
Physical thickness, α indicate that the incidence angle of laser, β indicate the angle of emergence of laser.
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| CN107478604B (en) * | 2017-07-10 | 2020-06-30 | 中国科学院上海光学精密机械研究所 | Device and method for measuring refractive index of transparent material |
| CN109612451A (en) * | 2019-01-14 | 2019-04-12 | 北京镭测科技有限公司 | Optical gyroscope |
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