CN102721461A - Detection device and detection method for semiconductor laser self-mixing infrasound - Google Patents
Detection device and detection method for semiconductor laser self-mixing infrasound Download PDFInfo
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- CN102721461A CN102721461A CN2012102102443A CN201210210244A CN102721461A CN 102721461 A CN102721461 A CN 102721461A CN 2012102102443 A CN2012102102443 A CN 2012102102443A CN 201210210244 A CN201210210244 A CN 201210210244A CN 102721461 A CN102721461 A CN 102721461A
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Abstract
The invention discloses a detection device for semiconductor laser self-mixing infrasound. The detection device comprises a semiconductor laser in which a photoelectric detector is packaged, a laser adjusting rack, a collimating lens, a convergent lens, a sensitive reflecting film, a laser driving circuit, a signal pre-processing circuit, a sound card, a data processing unit and an output terminal, wherein the sensitive reflecting film is arranged in an infrasound sound field zone; light generated by the semiconductor laser passes through the collimating lens to form parallel light; the parallel light is converged to the surface of a diaphragm through the convergent lens; part of light is reflected back to the inside of a laser cavity by adjusting the laser adjusting rack and is self mixed with the light generated in the laser cavity; the self-mixing light intensity is detected by the photoelectric detector and is converted into a voltage signal; the voltage signal is converted into a digital signal by the sound card; and the digital signal is processed by the data processing unit to output the measuring result. The detection device disclosed by the invention dispenses with auxiliary optical elements such as a spectrometer and a reference mirror of a traditional laser interferometer, and has compact and simple structure, low requirement on the processing precision of the device, low manufacturing cost and simplexes in operation.
Description
Technical field
The invention belongs to the infrasonic wave detection range, especially relate to a kind of employing laser self-mixing interference and measure infrasonic infrasonic wave detection apparatus of vibrating diaphragm vibration detection and detection method.
Background technology
Infrasonic sound is the sound that frequency is lower than 20Hz, and people's ear can't be heard.Many activities of the Nature, as volcanic explosion, earthquake, typhoon, rocket launching, wave bounce, wheel goes etc. that the generation of infrasonic sound is all arranged.At present, detecting infrasonic pick-up unit generally is condenser type infrasound sensor, optical fiber type infrasound sensor, two-beam interference formula infrasound sensor.
Yet above-mentioned detection device all has its weak point.Wherein, for the condenser type infrasound sensor, its weak point is: claimed structure is meticulous, designs tightly, and selection is strict, and particularly machining precision is very high, and its critical part all requires superfinishing.Relatively more responsive to variation of ambient temperature.Need carry out insulation, also will guarantee the cleanliness factor of superelevation simultaneously.And this type electric parameter sensor anti-electromagnetic interference capability is poor, makes it on using, receive very big restriction, as only limits to seismic monitoring, and the market price is high; For the optical fiber type infrasound sensor, its weak point is: higher to technical requirement, cost performance is low; And for two-beam interference formula infrasound sensor, its weak point is: need more auxiliary optical component, like spectrometer, polaroid, reference mirror etc., and light path needs collimation strictly, difficult the adjusting.
Summary of the invention
The objective of the invention is to overcome the defective of prior art, provide a kind of employing laser self-mixing interference to measure infrasonic infrasonic wave detection apparatus of vibrating diaphragm vibration detection and detection method.
For realizing above-mentioned purpose, technical scheme of the present invention is:
A kind of semiconductor laser includes optical system and electricity system from mixing infrasonic wave detection apparatus, and wherein, optical system includes semiconductor laser, laser instrument adjustment rack, collimation lens and the sensitive retroreflective sheeting that inside is packaged with photodetector; Electricity system comprises drive circuit for laser, signal pre-processing circuit, sound card, data processing unit and the outlet terminal that connects successively; Drive circuit for laser produces the constant-current driving semiconductor laser and sends laser, becomes directional light through behind the collimation lens, and this directional light converges on the sensitive retroreflective sheeting through convergent lens; Through regulating the laser instrument adjustment rack; Make part light by in the vibrating diaphragm return reflection surface laser cavity, feedback light is carried the vibration information of sensitive retroreflective sheeting, after light in the laser cavity mixes mutually; The self-mixed interference phenomenon takes place; Cause the variation of laser instrument output intensity, light intensity detects and converts into the current corresponding signal by being encapsulated in the inner photodetector of semiconductor laser, at first converts voltage signal into through signal pre-processing circuit; Through pre-amplification circuit voltage signal is amplified again; This signal converts digital signal into by the computer sound card collection, carries out data processing by data processing unit at last, exports infrasonic measurement result by outlet terminal.
Another technical scheme of the present invention does, provides a kind of semiconductor laser from mixing the infrasonic wave detection method, may further comprise the steps:
1) infrasonic wave acts on the sensitive retroreflective sheeting, and diaphragm produces displacement along with the variation of acoustic pressure, causes laser external cavity length generation subtle change;
2) after constant-current source circuit drove illumination that semiconductor laser sends and is mapped to sensitive reflective membrane surface, part light was reflected back toward in the laser cavity, forms self-mixed interference;
3) will be encapsulated in the inner detected light intensity change process of photodetector of semiconductor laser and become voltage signal, and amplify, after data acquisition, get into data processing unit;
4) data processing unit is handled the fluctuation striped that obtains self-mixing interference, demodulates the vibration displacement amplitude and the vibration frequency of said sensitive reflective membrane, calculates to obtain infrasonic intensity level and frequency values;
5) show infrasonic measurement result through outlet terminal at last.
Compared to prior art; Infrasonic wave detection apparatus of the present invention utilizes laser self-mixing interference to measure vibrating diaphragm vibration detection infrasonic wave; A kind of infrasonic new method that detects is provided, has not needed the auxiliary optical component such as spectrometer and reference mirror of conventional laser interferometer, photodetector is encapsulated in laser instrument inside makes compact overall structure simple; Requirement on machining accuracy to device is not high, and cost of manufacture is low and simple to operate.
Description of drawings
Fig. 1 is light path principle and the general structure schematic diagram that the present invention creates.
Fig. 2 is the data processing unit block diagram that the present invention creates.
Embodiment
For the purpose, technical scheme and the advantage that make this creation is clearer,, this creation is further elaborated below in conjunction with accompanying drawing and embodiment.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
With reference to shown in Figure 1, semiconductor laser of the present invention includes optical system and electricity system from mixing infrasonic wave detection apparatus.Wherein, optical system includes semiconductor laser, laser instrument adjustment rack, collimation lens and the sensitive retroreflective sheeting that inside is packaged with photodetector; Said semiconductor laser, collimation lens and convergent lens are installed on the laser instrument adjustment rack; Electricity system comprises drive circuit for laser 8, signal pre-processing circuit 9, sound card 10, data processing unit 11 and the outlet terminal 12 that connects successively.Said drive circuit for laser 8 is a constant-current source circuit, is used to regulate semiconductor laser drive current.The output steady current is 26mA during work.Described signal pre-processing circuit 9; Comprise current-voltage conversion circuit and pre-amplification circuit, during work, the self-mixing interference that photodetector is obtained converts voltage signal into; And it is amplified 100 times; The voltage signal that obtains is gathered through sound card 10, after data processing unit 11 is handled, obtains the vibration signal of sensitive retroreflective sheeting.The amplitude of vibration signal and frequency are final to output to outlet terminal 12 demonstrations through calculating infrasonic intensity and frequency.
Said sensitive retroreflective sheeting places in the infrasonic wave acoustic field, and infrasonic wave makes the diaphragm vibration, and this sensitivity retroreflective sheeting is by reflector layer, sensitive.The light that semiconductor laser 1 sends becomes directional light through collimation lens 3; Converge to sensitive retroreflective sheeting 5 surfaces through convergent lens 4 again; Through regulating the laser instrument adjustment rack, make part light by in the vibrating diaphragm return reflection surface laser cavity, produce from mixing with light in the laser cavity; Feedback light is carried the vibration information of sensitive retroreflective sheeting, after light in the laser cavity mixes mutually, the self-mixed interference phenomenon takes place; Cause the variation of laser instrument output intensity; Detect and convert into voltage signal from mixing light intensity by being encapsulated in the inner photodetector of laser instrument, obtain carrying the self-mixing interference of infrasonic wave information, convert digital signal into by the sound card collection; Handle by data processing unit again, and by outlet terminal output measurement result.
In embodiments of the present invention, semiconductor laser 1 is selected the QL65D5SA of Korea S QSI Corp. (wavelength 650nm, power 5mW) model laser instrument for use, and photodetector 2 adopts the photodiode that is integrated in the semiconductor laser.Adopt sensitive retroreflective sheeting 3 as exterior object, purpose is in order to control the light intensity of back light, to make that reflected light is appropriate light feedback.Semiconductor laser, collimation lens and convergent lens are installed in the collimator 6.When debugging apparatus,, make semiconductor laser send laser according to parameter regulation drive currents such as the threshold current of semiconductor laser and power 1.1 times at threshold current.After the laser instrument bright dipping, regulating light path, make optical convergence on the surface of sensitive retroreflective sheeting, then regulate laser instrument adjustment rack 7 part light is reflected back toward in the chamber, guaranteeing to take place self-mixed interference, and is appropriate light feedback.
During application, semiconductor laser of the present invention comprises the steps: from mixing the infrasonic wave detection method
(1) infrasonic wave acts on the sensitive retroreflective sheeting, and diaphragm produces displacement along with the variation of acoustic pressure, causes laser external cavity length generation subtle change;
(2) after constant-current source circuit drove illumination that semiconductor laser sends and is mapped to sensitive reflective membrane surface, part light was reflected back toward in the laser cavity, forms self-mixed interference;
(3) will be encapsulated in the inner detected light intensity change process of photodetector of semiconductor laser and become voltage signal, and amplify, after data acquisition, get into data processing unit;
(4) data processing unit is handled the fluctuation striped that obtains self-mixing interference, demodulates the vibration displacement amplitude and the vibration frequency of said sensitive reflective membrane, calculates to obtain infrasonic intensity level and frequency values;
(5) show infrasonic measurement result through outlet terminal at last;
With reference to shown in Figure 2, it is the processing signals flow process of data processing unit 11, and it is 44kHz that the computer sound card SF at first is set, and each 4096 sampled points carry out data acquisition, and number collection begins to carry out The disposal of gentle filter after finishing, and removes the noise of sudden change.Then, carry out difference to data processed, get certain threshold test and go out each trip point, last, ask the number of transitions that detects and add up, demodulate vibrational waveform, obtain vibration information.
In embodiments of the present invention, laser self-mixing interference is meant in the laser applications system, the light of laser instrument output by exterior object reflection or scattering after; Wherein a part of light feeds back to the resonator cavity of laser instrument again; Feedback light is carried the vibration information of exterior object, after light in the laser cavity mixes mutually, interferes phenomenon; Because of light signal and traditional two-beam interference of output has similarity, so be referred to as self-mixed interference.Adopt the crossing current source to drive semiconductor laser, have the output intensity of the semiconductor laser under the light feedback to change, be called the laser self-mixing interference signal with external cavity is long.When the corresponding exterior object of a fluctuation of laser self-mixing interference signal striped moves half wavelength, through the periodicity of record fluctuation, can Displacement Measurement.When light feedback level when being a certain amount of; The sinusoidal waveform of interference fringe for tilting; The direction that tilts is corresponding with sense of displacement, because interference signal comprises the directional information of displacement, and thus can be through accumulation process to interference fringe; Multiply by fixed coefficient again and just can demodulate the vibrational waveform of exterior object, thereby obtain its Oscillation Amplitude and frequency.
The embodiment of the invention utilizes laser self-mixing interference to measure vibrating diaphragm vibration detection infrasonic wave; The auxiliary optical component such as spectrometer and reference mirror that does not need the conventional laser interferometer; Photodetector is encapsulated in laser instrument inside makes compact overall structure simple; Requirement on machining accuracy to device is not high, and cost of manufacture is low and simple to operate.
The above is merely preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of within spirit of the present invention and principle, being done, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.
Claims (5)
1. a semiconductor laser is from mixing infrasonic wave detection apparatus; Include optical system and electricity system, it is characterized in that: optical system includes semiconductor laser, laser instrument adjustment rack, collimation lens and the sensitive retroreflective sheeting that inside is packaged with photodetector; Electricity system comprises drive circuit for laser, signal pre-processing circuit, sound card, data processing unit and the outlet terminal that connects successively; Drive circuit for laser produces the constant-current driving semiconductor laser and sends laser, becomes directional light through behind the collimation lens, and this directional light converges on the sensitive retroreflective sheeting through convergent lens; Through regulating the laser instrument adjustment rack; Make part light by in the vibrating diaphragm return reflection surface laser cavity, feedback light is carried the vibration information of sensitive retroreflective sheeting, after light in the laser cavity mixes mutually; The self-mixed interference phenomenon takes place; Cause the variation of laser instrument output intensity, light intensity detects and converts into the current corresponding signal by being encapsulated in the inner photodetector of semiconductor laser, at first converts voltage signal into through signal pre-processing circuit; Through pre-amplification circuit voltage signal is amplified again; This signal converts digital signal into by the computer sound card collection, carries out data processing by data processing unit at last, exports infrasonic measurement result by outlet terminal.
2. semiconductor laser as claimed in claim 1 mixes infrasonic wave detection apparatus certainly,, it is characterized in that: said semiconductor laser, collimation lens and convergent lens are installed on the laser instrument adjustment rack; Said sensitive retroreflective sheeting includes reflector layer, sensitive.
3. semiconductor laser as claimed in claim 2 is from mixing infrasonic wave detection apparatus, and it is characterized in that: said drive circuit for laser is a constant-current source circuit, is used to regulate semiconductor laser drive current; Described signal pre-processing circuit comprises current-voltage conversion circuit and pre-amplification circuit.
4. semiconductor laser as claimed in claim 3 is from mixing infrasonic wave detection apparatus; It is characterized in that: said sensitive retroreflective sheeting places in the infrasonic wave acoustic field; Infrasonic wave makes the diaphragm vibration; Thereby cause that said sensitive retroreflective sheeting has microvibration with respect to said semiconductor laser, make said semiconductor laser front end face subtle change take place, and then said laser instrument output intensity is changed to the distance on said sensitive retroreflective sheeting surface.
5. a semiconductor laser is characterized in that from mixing the infrasonic wave detection method, may further comprise the steps:
1) infrasonic wave acts on the sensitive retroreflective sheeting, and diaphragm produces displacement along with the variation of acoustic pressure, causes laser external cavity length generation subtle change;
2) after constant-current source circuit drove illumination that semiconductor laser sends and is mapped to sensitive reflective membrane surface, part light was reflected back toward in the laser cavity, forms self-mixed interference;
3) will be encapsulated in the inner detected light intensity change process of photodetector of semiconductor laser and become voltage signal, and amplify, after data acquisition, get into data processing unit;
4) data processing unit is handled the fluctuation striped that obtains self-mixing interference, demodulates the vibration displacement amplitude and the vibration frequency of said sensitive reflective membrane, calculates to obtain infrasonic intensity level and frequency values;
5) show infrasonic measurement result through outlet terminal at last.
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| CN103424177A (en) * | 2013-09-11 | 2013-12-04 | 南京大学 | Method and device for improving sensitivity of reflecting-type laser vibration measurement system |
| CN105698917A (en) * | 2016-03-17 | 2016-06-22 | 辽宁石油化工大学 | Infrasonic wave detection apparatus and detection method thereof |
| CN106643543A (en) * | 2016-12-30 | 2017-05-10 | 东北石油大学 | Method for detecting deformation of surface of magnetic disk storage |
| CN106949955A (en) * | 2017-04-18 | 2017-07-14 | 中国工程物理研究院电子工程研究所 | A kind of MEMS platform based on optical detection |
| CN107560713A (en) * | 2017-10-27 | 2018-01-09 | 罗沛棋 | Vibration signal extraction element based on gradual change transmitance filter |
| CN107817009A (en) * | 2017-09-30 | 2018-03-20 | 中国科学院长春光学精密机械与物理研究所 | A kind of laser detects monitoring device from mixing |
| CN108225543A (en) * | 2018-03-28 | 2018-06-29 | 中国科学院长春光学精密机械与物理研究所 | The orthogonal detection vibration measurement device and method of a kind of self-mixed interference |
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| CN103424177B (en) * | 2013-09-11 | 2015-06-17 | 南京大学 | Method and device for improving sensitivity of reflecting-type laser vibration measurement system |
| CN103424177A (en) * | 2013-09-11 | 2013-12-04 | 南京大学 | Method and device for improving sensitivity of reflecting-type laser vibration measurement system |
| CN105698917A (en) * | 2016-03-17 | 2016-06-22 | 辽宁石油化工大学 | Infrasonic wave detection apparatus and detection method thereof |
| CN106643543A (en) * | 2016-12-30 | 2017-05-10 | 东北石油大学 | Method for detecting deformation of surface of magnetic disk storage |
| CN106949955A (en) * | 2017-04-18 | 2017-07-14 | 中国工程物理研究院电子工程研究所 | A kind of MEMS platform based on optical detection |
| CN107817009B (en) * | 2017-09-30 | 2020-10-13 | 中国科学院长春光学精密机械与物理研究所 | Laser self-mixing detection monitoring device |
| CN107817009A (en) * | 2017-09-30 | 2018-03-20 | 中国科学院长春光学精密机械与物理研究所 | A kind of laser detects monitoring device from mixing |
| CN107560713A (en) * | 2017-10-27 | 2018-01-09 | 罗沛棋 | Vibration signal extraction element based on gradual change transmitance filter |
| CN108225543A (en) * | 2018-03-28 | 2018-06-29 | 中国科学院长春光学精密机械与物理研究所 | The orthogonal detection vibration measurement device and method of a kind of self-mixed interference |
| CN108319965A (en) * | 2018-03-28 | 2018-07-24 | 江苏珩图智能科技有限公司 | A kind of device and method obtaining sound using image |
| CN108225543B (en) * | 2018-03-28 | 2019-06-25 | 中国科学院长春光学精密机械与物理研究所 | A kind of the orthogonal detection vibration measurement device and method of self-mixed interference |
| CN108775954A (en) * | 2018-06-06 | 2018-11-09 | 岭南师范学院 | A kind of adjustable dual wavelength LD of resolution ratio is from mixing vibration measuring instrument and its measurement method |
| CN108917915A (en) * | 2018-07-19 | 2018-11-30 | 安徽大学 | A kind of laser of visualization focusing is from mixed signal sound detection method and system |
| CN108917915B (en) * | 2018-07-19 | 2021-03-30 | 安徽大学 | Visual focusing laser self-mixing signal sound detection method and system |
| CN109471157A (en) * | 2018-12-27 | 2019-03-15 | 中国科学院声学研究所 | A kind of high sensitivity infrasound sensor |
| CN109945964B (en) * | 2019-03-01 | 2021-01-29 | 华为技术有限公司 | Sound wave signal detection device and method and intelligent terminal |
| CN109945964A (en) * | 2019-03-01 | 2019-06-28 | 华为技术有限公司 | Acoustic signals detection device, method and intelligent terminal |
| CN110346144A (en) * | 2019-08-15 | 2019-10-18 | 岭南师范学院 | A kind of bearing fault detection device and detection method |
| CN113624325A (en) * | 2021-08-16 | 2021-11-09 | 安徽至博光电科技股份有限公司 | Laser acoustic sensor and system |
| CN113624325B (en) * | 2021-08-16 | 2023-11-28 | 安徽至博光电科技股份有限公司 | Laser acoustic sensor and system |
| WO2024001688A1 (en) * | 2022-06-28 | 2024-01-04 | 华为技术有限公司 | Passive communication terminal, passive communication system, and passive communication method |
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Application publication date: 20121010 |