CN208076388U - A kind of Terahertz detection device - Google Patents
A kind of Terahertz detection device Download PDFInfo
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- CN208076388U CN208076388U CN201820450174.1U CN201820450174U CN208076388U CN 208076388 U CN208076388 U CN 208076388U CN 201820450174 U CN201820450174 U CN 201820450174U CN 208076388 U CN208076388 U CN 208076388U
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Abstract
The utility model is related to safety inspection technical fields, provide a kind of Terahertz detection device, it include the laser system for generating laser, Dispersion Compensation Systems for carrying out dispersion compensation to laser, beam splitter, optical fibre drawing system for carrying out delayed sweep to laser, for generating and receiving THz wave and the specimen inspection system being detected to detected sample and the data processing system for being analyzed test data, laser system is connect by optical fiber with Dispersion Compensation Systems, Dispersion Compensation Systems are connect by optical fiber with beam splitter, beam splitter by optical fiber simultaneously and optical fibre drawing system, specimen inspection system connects, optical fibre drawing system is connect by optical fiber with specimen inspection system, specimen inspection system is connect by optical fiber with data processing system simultaneously；Many kinds of substance can be not only identified, but also the use demand of different scenes can be met with automatic identification detected sample to substantially increase the efficiency of safety inspection.
Description
Technical field
The utility model is related to safety inspection technical fields, are to be related to a kind of Terahertz detection device more specifically.
Background technology
Safety of the detection of explosives, inflammable items concerning public place, therefore the place more intensive in flow of the people, such as
Airport, subway, bus station etc., it usually needs safety inspection is carried out, to exclude hidden danger.Liquid dangerous material are usually at normal temperatures
Liquid has the characteristics that uniform component, good fluidity, convenient transportation, easily fabricated and camouflage, concealment are strong；In addition, liquid is endangered
The raw material of dangerous product can be separated and be transported, or can be mixed with multiple compounds, to increase the difficulty of safety inspection work
Degree.
Currently, excluding the usual way of explosives, inflammable items is：Liquid type allows carrier to drink some, and is not endangered with showing
Evil, however not only efficiency is low for this way, but also be easy to cause the resentment of passenger；Solid kind, in the peace that Mag & Bag Area provides
Inspection machine needs staff only simply to determine whether contraband by its external form information.Current rays safety detection apparatus both domestic and external
In, although there is the automatic recognition system for the substantial risks substance such as explosive, explosive, drugs, technology is not perfect, and
It is expensive.In addition, a large amount of common dangerous material in people's daily life, can but reach without any safety check product
Automatic identification is required for carrying out semi-artificial identification to it, even opens packet and checks manual identified.
The technology that existing security detection equipment includes has X-ray, Raman spectroscopy, dielectric constant Detection Techniques etc..
But X-ray damages by force organism, those are not allowed with volatile liquid dangerous material, the especially liquid in closed container
State dangerous material basically can not detect, and the interference of metal sundries is then highly susceptible to for metal detection and increases rate of false alarm；Swash
Light Raman spectrum uses low power laser light source, and laser beam can penetrate transparent bottling liquid, to nontransparent container but without
It can be powerless；Dielectric constant technical role is limited in scope, and is typically used to detect the liquid article in container, needs to visit close to sample
It surveys, and penetration capacity is limited.
The above deficiency, has much room for improvement.
Utility model content
The purpose of this utility model is to provide a kind of Terahertz detection devices, to solve safety existing in the prior art
Check the limited technical problem of the dangerous material type of inefficiency and detection.
To achieve the above object, the technical solution adopted in the utility model is：A kind of Terahertz detection device is provided, including
For generating the laser system of laser, the Dispersion Compensation Systems for carrying out dispersion compensation to the laser, beam splitter, being used for
The optical fibre drawing system of delayed sweep is carried out, for generating and receiving THz wave and carried out to detected sample to the laser
The specimen inspection system of detection and data processing system for being analyzed test data, the laser system pass through optical fiber
It is connect with the Dispersion Compensation Systems, the Dispersion Compensation Systems are connect by optical fiber with the beam splitter, the smooth beam splitting
Device is connect with the optical fibre drawing system, the specimen inspection system simultaneously by optical fiber, and the optical fibre drawing system passes through light
It is fine to be connect with the specimen inspection system, while the specimen inspection system is connect with the data processing system.
Further, the laser system includes sequentially connected laser, saturable absorber, photo-coupler, gain
Optical fiber and fiber grating, the side that the photo-coupler is connect with the saturable absorber are also associated with pumping source.
Further, the laser system further includes repetition rate locking mechanism, and the repetition rate locking mechanism is used for
The frequency for the laser that the laser generates is locked, the laser is equipped with the piezoelectricity pottery for the chamber length that can be used for adjusting its laser cavity
Porcelain, the repetition rate locking mechanism are connect with the piezoelectric ceramics, while the repetition rate locking mechanism and the laser
Device connects.
Further, the repetition rate locking mechanism includes sequentially connected photodetector, bandpass filter, mixing
Device, loop filter and high-voltage amplifier, the photodetector are connected with the laser, the high-voltage amplifier with it is described
Piezoelectric ceramics connects, and the side that the frequency mixer connects the bandpass filter is also associated with reference generator, the base
Calibration signal generator is locked on rubidium clock.
Further, the Dispersion Compensation Systems include the fiber annular mechanism for adjusting the laser transmission direction,
For carrying out dispersion compensation and the first chirped fiber grating and the second chirped fiber light of chromatic dispersion compensation quantity on the contrary to the laser
Grid, the fiber annular mechanism are equipped with input terminal for being connect with optical fiber, and the optical fiber is used for transmission the laser, and described the
One chirped fiber grating and second chirped fiber grating are connect with the fiber annular mechanism, and the laser leads to successively
It is emitted from the fiber annular mechanism after crossing first chirped fiber grating and second chirped fiber grating, described
The absolute value of the chromatic dispersion compensation quantity of one chirped fiber grating and second chirped fiber grating is unequal.
Further, the specimen inspection system includes for generating the photoconductive transmitting antenna of THz wave, for connecing
Receive the photoconductive reception antenna of the THz wave and the optical module for being focused to the THz wave, the photoelectricity
It leads transmitting antenna to connect with the beam splitter, the photoconduction reception antenna is connect with the optical fibre drawing system and the light
Conductance reception antenna is connect with the data processing system.
Further, the optical module includes that the THz wave for generating the photoconductive transmitting antenna focuses on
The first lens group on the detected sample and described for focusing on the THz wave after the detected sample
Second lens group of photoconductive reception antenna.
Further, the optical fibre drawing system includes the first coupler, two optical fiber for being split to laser
Stretcher, for laser close the second coupler of beam, the photodetector for converting optical signals to electric signal and
Display device for converting electrical signals to visualized graphs, the beam splitter are connected with first coupler by optical fiber
Connect, first coupler is connect with two fiber stretchers by optical fiber simultaneously, two fiber stretchers with
Second coupler is connected by optical fiber, and second coupler is connect with the photodetector by optical fiber, the light
Electric explorer is connect with the display device.
Further, it is additionally provided with locking phase amplification module between the photoconductive reception antenna and the DPA data processing activity.
Further, the data processing system includes data processing module and the detected sample is identified
Computer, the data processing module are connect by cable with the computer, and the data processing module is put with the locking phase
Big module connection.
A kind of advantageous effect of Terahertz detection device provided by the utility model is：
(1) detected sample is detected as a result of THz wave, terahertz time-domain spectroscopic technology has can be into
Row non-destructive testing and sample detection obtain the features such as material information is convenient and efficient, low to external condition requirement, so that terahertz
Hereby detection device can not only be identified many kinds of substance, but also expand the application scenarios of Terahertz detection device.
(2) Terahertz detection device can carry out automatic identification to detected sample, without manually carrying out auxiliary knowledge
Not, to substantially increase the efficiency of safety inspection, meet the use demand of different scenes.
Description of the drawings
It, below will be to embodiment or the prior art in order to illustrate more clearly of the technical scheme in the embodiment of the utility model
Attached drawing needed in description is briefly described, it should be apparent that, the accompanying drawings in the following description is only that this practicality is new
Some embodiments of type for those of ordinary skill in the art without creative efforts, can be with root
Other attached drawings are obtained according to these attached drawings.
Fig. 1 is the system principle schematic diagram for the Terahertz detection device that the utility model embodiment provides；
Fig. 2 is the laser mode locking principle schematic for the Terahertz detection device that the utility model embodiment provides；
Fig. 3 is the repetition rate locking mechanism schematic diagram for the Terahertz detection device that the utility model embodiment provides；
Fig. 4 is a kind of structural representation of the Dispersion Compensation Systems for the Terahertz detection device that the utility model embodiment provides
Figure；
Fig. 5 is that another structure of the Dispersion Compensation Systems for the Terahertz detection device that the utility model embodiment provides is shown
It is intended to；
Fig. 6 is the negative dispersion chirped light of the Dispersion Compensation Systems for the Terahertz detection device that the utility model embodiment provides
The structural schematic diagram of fine grating；
Fig. 7 is the positive dispersion chirped light of the Dispersion Compensation Systems for the Terahertz detection device that the utility model embodiment provides
The structural schematic diagram of fine grating；
Fig. 8 is the structural schematic diagram of the optical fibre drawing system for the Terahertz detection device that the utility model embodiment provides；
Fig. 9 is the structural schematic diagram of the fiber stretcher for the Terahertz detection device that the utility model embodiment provides；
Figure 10 is the structural schematic diagram of the locking phase amplification module for the Terahertz detection device that the utility model embodiment provides；
Figure 11 is that the Terahertz detection device that the utility model embodiment provides measures beverage schematic diagram；
Figure 12 is the reflected impulse when Terahertz detection device that the utility model embodiment provides measures detected sample
Waveform diagram.
Specific implementation mode
In order to make technical problem to be solved in the utility model, technical solution and advantageous effect be more clearly understood, with
Lower combination accompanying drawings and embodiments, the present invention will be further described in detail.It should be appreciated that specific reality described herein
Example is applied only to explain the utility model, is not used to limit the utility model.
It should be noted that when element is referred to as " being set to " another element, it can be directly on another element
Or it is connected on another element.When an element is known as " being connected to " another element, it can directly be connected
It is connected to another element or is indirectly connected on another element.In addition, term " first ", " second " are only used for description mesh
, it is not understood to indicate or imply relative importance or implicitly indicates the quantity of indicated technical characteristic.It limits as a result,
There is the feature of " first ", " second " to can explicitly or implicitly include one or more this feature surely.It is new in this practicality
In the description of type, the meaning of " plurality " is two or more, unless otherwise specifically defined.
Referring to Fig. 1, a kind of Terahertz detection device, include for generate the laser system 1 of laser, for laser into
The Dispersion Compensation Systems 2 of row dispersion compensation, the optical fibre drawing system 4 for carrying out delayed sweep to laser, are used beam splitter 3
In emit and receive THz wave and specimen inspection system 5 that detected sample 6 is detected and for test data into
The data processing system 7 of row analysis, laser system 1 are connect by optical fiber 10 with Dispersion Compensation Systems 2, and Dispersion Compensation Systems 2 are logical
Optical fiber 10 is crossed to connect with beam splitter 3, beam splitter 3 by optical fiber 10 simultaneously with optical fibre drawing system 4, specimen inspection system 5
Connection, optical fibre drawing system 4 are connect by optical fiber 10 with specimen inspection system 5, while specimen inspection system 5 and data processing system
7 connection of system.
A kind of operation principle of Terahertz detection device provided in this embodiment is as follows：What laser system 1 generated first swashs
Light is transferred to Dispersion Compensation Systems 2 by optical fiber 10, and carries out dispersion compensation in advance by Dispersion Compensation Systems 2；Then laser
By being divided into two beams after beam splitter 3, beam of laser is used to emit THz wave, THz wave after reaching specimen inspection system 5
The information of detected sample 6 can be carried after being irradiated on detected sample 6, then carry the terahertz of the information of detected sample 6
Hereby wave is received by specimen inspection system 5；Another beam of laser by reaching specimen inspection system 5 after optical fibre drawing system 4, and with take
The THz wave of information with detected sample 6 carries out coupling and forms test data；Then test data is transferred to data processing
System 7 is handled, and detected sample 6 is identified, to realize judgement and alarm to combustible and explosive articles.
Wherein, due to the peculiar property of THz wave, terahertz time-domain spectroscopic technology has the following advantages：
(1) bandwidth：With about from the frequency bandwidth of 0.1THz~5THz.
(2) signal-to-noise ratio is high：Terahertz time-domain spectroscopy system signal-to-noise ratio when less than 3THz may be up to 104, far above in Fu
Leaf transformation infrared spectrum technology, and there is preferable stability.
(3) it can carry out non-destructive testing and sample detects：It can effectively be detected using terahertz time-domain spectroscopic technology to be detected
Sample is reflected in the information of the various physical messages and chemical information etc. of terahertz wave band, so as to for carrying out substance
Qualitive test is analyzed.Further, since the safety of THz wave and penetrability are so as to fit lossless for being carried out to biological tissue
Detection.Terahertz time-domain spectroscopic technology also have the characteristics that detectivity it is high and can steady operation at room temperature, therefore can
To be widely used in the detection of sample.
(4) it is convenient and efficient to obtain medium information：It can easily and quickly be obtained using terahertz time-domain spectroscopic technology a variety of
Material information, such as dielectric substance, large biological molecule and semi-conducting material amplitude and phase information, can also be directly anti-
Mirror the current-carrying sub-information in conductive material；Meanwhile the coherence of terahertz time-domain spectroscopy makes electric field waveform contain Terahertz
The complete informations such as intensity, phase, the time of pulse make it be converted to spectrum signal by Fourier transform, can be absorbed
Spectrum and dispersion spectrum.
(5) external condition is required low：Terahertz time-domain spectroscopy system can work at room temperature, eliminate complicated refrigeration
System.
(6) non-cpntact measurement：Terahertz emission can directly reflect the information of carrier in conductive material, thus Terahertz
The untouchable measurement that time-domain spectroscopy system ratio is based on Hall (Hall) effect is more convenient, effective.
(7) safe and harmless：The photon energy of THz wave is low, and 1THz corresponds to the energy of 4.1meV, when detecting substance not
The ingredient of tested substance can be destroyed, and is also safe to operating personnel.
A kind of advantageous effect of Terahertz detection device provided in this embodiment is：
(1) detected sample 6 is detected as a result of THz wave, terahertz time-domain spectroscopic technology has can be into
Row non-destructive testing and sample detection obtain the features such as material information is convenient and efficient, low to external condition requirement, so that terahertz
Hereby detection device can not only be identified many kinds of substance, but also expand the application scenarios of Terahertz detection device.
(2) Terahertz detection device can carry out automatic identification to detected sample 6, without manually carrying out auxiliary knowledge
Not, to substantially increase the efficiency of safety inspection, meet the use demand of different scenes.
It is equipped with lithium battery in Terahertz detection device provided in this embodiment, the outdoor detection of progress can be facilitated, while also may be used
To prevent from not being detected due to instant cut-off, and equipment can be protected.The bottom of Terahertz detection device
Be additionally provided with universal wheel so that Terahertz detection device can be moved arbitrarily, so as to as needed in any position into
Row detection.
Referring to Fig. 2, further, laser system 1 includes sequentially connected laser 11, saturable absorber 12, light
Coupler 13, gain fibre 14 and fiber grating 15, the side that photo-coupler 13 is connect with saturable absorber 12 are also associated with
Pumping source 16.Preferably, laser 11 is femto-second laser, so as to generate femto-second laser pulse.
Since saturable absorber 12 is big to weak absorption, and it is few to strong light absorption, therefore when what laser 11 generated swashs
When luminous intensity is too low, laser can be absorbed by saturable absorber 12, and when the laser intensity that laser 11 generates is got higher, laser
Saturable absorber 12 can be just penetrated, therefore uses saturable absorber 12, it is ensured that the output power satisfaction of laser 11 is wanted
It asks.In the present embodiment, the output power of laser 11 is higher than 80mW, and the pulse width of femto-second laser pulse is less than 100fs.
Since pumping source 16 is coupled with by the laser of saturable absorber 12 in photo-coupler 13, after coupling
Laser carries out gain by gain fibre 14, and is filtered by fiber grating 15, it is hereby achieved that specific wavelength swashs
Light meets requirement.
Referring to Fig. 3, further, laser system 1 further includes repetition rate locking mechanism, and repetition rate locking mechanism can
Frequency for the laser that locked laser 11 generates；Laser 11 is equipped with the piezoelectricity pottery for the chamber length that can be used for adjusting its laser cavity
Porcelain, preferably PZT piezoelectric ceramics 111, PZT piezoelectric ceramics work under the control of PZT drivings 110；Repetition rate locking mechanism
It is connect with PZT piezoelectric ceramics 111, while repetition rate locking mechanism is connect with laser 11.The one of the laser that laser generates
Fraction light is entered after being divided by coupler in repetition rate locking mechanism, and phase is generated after repetition rate locking mechanism
The high-voltage signal answered, then high-voltage signal is by 110 control PZT piezoelectric ceramics of PZT drivings, 111 movement, to change laser cavity
Chamber it is long, and then the frequency of laser is adjusted so that the repetition rate for exporting laser is stablized.
In the present embodiment, repetition rate locking mechanism includes sequentially connected photodetector 171, bandpass filter
172, frequency mixer 173, loop filter 174 and high-voltage amplifier 175, photodetector 171 are connected with laser 11, and height presses
Big device 175 is connect with PZT piezoelectric ceramics 111, and the side that frequency mixer 173 connects bandpass filter 172 is also associated with reference signal
Generator 176, reference generator 176 are locked on rubidium clock 177.
It is radiated at photodetector 171 after thering is sub-fraction light to be divided by coupler in the laser that femto-second laser generates
On, and captured by photodetector 171.171 output frequency of photodetector is that repetition rate integral multiple (is denoted as Nfrep) letter
Number, which can be filtered by bandpass filter 172, to obtain signal (the i.e. Nf for needing frequencyrepSignal).
Preferably, 4 N, i.e. 171 output frequency of photodetector are 4 times of repetition rates, and what is obtained after bandpass filter 172 is
The four-time harmonic of repetition rate；It is of course also possible to obtain the harmonic wave of more high order；In fact, the overtone order of mixing input is higher,
System is more sensitive to the variation of frequency, to obtain higher stability after forming closed-loop control system.
The reference signal that signal after bandpass filter 172 is generated with reference generator 176 enters frequency mixer
173 are mixed, to which difference frequency signal can be obtained.Reference generator 76 is locked on rubidium clock 177, and according to be locked
Repetition rate setting reference signal frequency, in the present embodiment, the frequency of reference signal is 1000MHz.Difference frequency signal into
Compensating control signal is exported after entering loop control unit 174, compensating control signal is believed by obtaining high pressure after high-voltage amplifier 175
Number, for controlling PZT drivings 110, to control PZT piezoelectric ceramics 111, changed by the micro-displacement of PZT piezoelectric ceramics 111
The chamber of laser cavity is long, and so as to inhibit the minor fluctuations of repetition rate, final dynamic tracks upper reference signal and (is locked to base
Calibration signal) so that repetition rate frepIt obtains and 177 same stability of rubidium clock, it is ensured that the repetition rate for exporting laser is steady
It is fixed.
Wherein loop control unit 174 is the core of entire repetition rate locking mechanism, not only has the function of low-pass filtering,
But also the dynamic response characteristic and stability characteristic (quality) of system can be improved.
Further, loop control unit 174 includes pi controller and DC bias circuit, wherein proportional integration control
The function of device processed is the dynamic response characteristic of improvement system, and DC bias circuit is to find suitable frequency before locking
Point, to realize that quick lock in is prepared.Pi controller includes bandwidth selection part, integral element part and low-frequency gain
Limit the part (Low Frequency Gain Limit, be abbreviated as LFGL)；Wherein bandwidth selection part is suitable in order to select
Bandwidth loop is switched to the position in broadband when unlocked, be convenient for rapid frequency-sweeping, loop is switched to again when locked
The position of narrowband reduces error, improves locking performance；Low-frequency gain restricted part prevents from locking for limiting low-frequency gain
Moment integral saturation occurs since condition is improper, limit low-frequency gain before locking, find keyed end, it is to be locked after solution
Except limitation, hence into pure integral element.Above-mentioned setting makes the operation of repetition rate locking process more flexible, is conducive to fast
Speed finds keyed end, efficiently and accurately completes locking.The stability of the repetition rate of common femto-second laser is in 20Hz or so
(i.e. repetition rate ± 20Hz), in the present embodiment, femtosecond laser repetition rate can be stablized in 100MHz ± 1mHz, to greatly
Improve the stability of femto-second laser.
Referring to Fig. 4, further, Dispersion Compensation Systems 2 include the fiber annular machine for adjusting laser transmission direction
Structure, for carrying out dispersion compensation and the first chirped fiber grating 221 and the second chirped fiber of chromatic dispersion compensation quantity on the contrary to laser
Grating 222, fiber annular mechanism are equipped with the input terminal for being connect with optical fiber 10, and optical fiber 10 is used for transmission laser 100, the first Zhou
It sings fiber grating 221 and the second chirped fiber grating 222 is connect with fiber annular mechanism, and laser 100 passes sequentially through first
It is emitted from fiber annular mechanism after chirped fiber grating 221 and the second chirped fiber grating 222, the first chirped fiber grating
221 and second chirped fiber grating 222 it is unequal to the absolute value of the chromatic dispersion compensation quantity of laser 100.
The operation principle of Dispersion Compensation Systems 2 is as follows：The optical fiber 10 for transmitting laser 100 is connected with fiber annular mechanism first
It connects, while the first chirped fiber grating 221, the second chirped fiber grating 222 being sequentially connected with fiber annular mechanism, to make
After laser 100 entered by optical fiber 3 in fiber annular mechanism, pass sequentially through the first chirped fiber grating 221 and the 2nd Zhou
Fiber grating 222 of singing carries out dispersion compensation, is then emitted from fiber annular mechanism.Due to 221 He of the first chirped fiber grating
The dispersion compensation of second chirped fiber grating 222 is opposite and chromatic dispersion compensation quantity is unequal, therefore when laser 100 passes sequentially through first
After chirped fiber grating 221 and the second chirped fiber grating 222, total dispersion compensation rate is the first chirped fiber grating 221
The sum of the chromatic dispersion compensation quantity of chromatic dispersion compensation quantity and the second chirped fiber grating 222, and total dispersion compensation rate can reach fs/nm
The magnitude of (femtosecond/nanometer) compensates so as to the small dispersion measure to femtosecond laser.
The advantageous effect being arranged in this way is：Due to being provided with for carrying out dispersion compensation and dispersion compensation to laser 100
Opposite the first chirped fiber grating 221 and the second chirped fiber grating 222, therefore when laser 100 passes sequentially through the first chirp
After fiber grating 221 and the second chirped fiber grating 222, total dispersion compensation rate can reach the magnitude of fs/nm, so as to right
The small dispersion measure of femtosecond laser compensates, the reliability of effective guarantee laser transmission.
Please refer to figure, 4, in one embodiment, fiber annular mechanism includes the first optical fiber circulator 211, the first optical fiber
Circulator 211 includes the first input port 2110, first port 2111,2112 and of second port being arranged along laser transmission direction
Third port 2113, first input port 2110 are connect with optical fiber 10, and first port 2111 and the first chirped fiber grating 221 connect
It connects, second port 2112 is connect with the second chirped fiber grating 222.By the first optical fiber circulator 211 by the first chirped fiber
Grating 221 and the connection of the second chirped fiber grating 222, not only may be implemented the small dispersion compensation to laser 100, but also structure
It is compact, it is easy for installation.Preferably, the first optical fiber circulator 211 is four fiber port circulators.
Referring to Fig. 5, in one embodiment, fiber annular mechanism includes the second optical fiber circulator 212 and third optical fiber
Circulator 213, the second optical fiber circulator 212 include the second input port 2120 being arranged along laser transmission direction, the 4th port
2121 and fifth port 2122, third optical fiber circulator 213 include the third input port 2130 being arranged along laser transmission direction,
7th port 2131 and the 8th port 2132, the second input port 2120 are connect with optical fiber 10, the 4th port 2121 and the first Zhou
Fiber grating 221 of singing connects, and fifth port 2122 is connect with third input port 2130, the 7th port 2131 and the second chirped light
Fine grating 222 connects.Preferably, the second optical fiber circulator 212 is three fiber port circulators, and third optical fiber circulator 213 is
Three fiber port circulators, the second optical fiber circulator 212 and third optical fiber circulator 213 are connected with each other by optical fiber 103.Pass through
Two optical fiber circulators are separately connected the first chirped fiber grating 221 and the second chirped fiber grating 222, not only may be implemented pair
The small dispersion compensation of laser 100, and can be attached as needed, installation is more flexible.
It should be understood that the second optical fiber circulator 212 and third optical fiber circulator 213 or other types of optical fiber
Circulator, such as four fiber port circulators only sequentially use three ports therein when in use.
Fig. 6 and Fig. 7 are please referred to, in one embodiment, the variations in refractive index period edge in the first chirped fiber grating 221
100 incident direction of laser gradually increases, and the variations in refractive index period in the second chirped fiber grating 222 is along 100 incidence side of laser
To being gradually reduced.Specifically, the first chirped fiber grating 221 is negative dispersion chirped fiber grating, the different frequency in laser 100
Laser components be totally reflected in the different location of negative dispersion chirped fiber grating, wherein high frequency lasers component 1001 occurs entirely
The position of reflection is deeper than the position that low frequency lasers component 1002 is totally reflected so that the light path of high frequency lasers component 1001 is big
In the light path of low frequency lasers component 1002, to generate negative dispersion；Second chirped fiber grating 222 is positive dispersion chirped fiber light
The laser components of grid, the different frequency in laser 100 are totally reflected in the different location of positive dispersion chirped fiber grating, wherein
The position that high frequency lasers component 1001 is totally reflected is more shallow than the position that low frequency lasers component 1002 is totally reflected so that high
The light path of frequency laser component 1001 is less than the light path of low frequency lasers component 1002, to generate positive dispersion.In fact, actually making
Used time, it is only necessary to reversely connect negative dispersion chirped fiber grating with optical fiber circulator, you can obtain positive dispersion chirped fiber light
Grid.
In one embodiment, the variations in refractive index period in the first chirped fiber grating 221 is along 100 incident direction of laser
It is gradually reduced, i.e. the first chirped fiber grating 221 is positive dispersion chirped fiber grating；Folding in second chirped fiber grating 222
It penetrates rate period of change along 100 incident direction of laser gradually to increase, i.e. the second chirped fiber grating 222 is negative dispersion chirped fiber light
Grid.
Because therefore the first chirped fiber grating 221 and the dispersion compensation of the second chirped fiber grating 222 generation are on the contrary, work as
Laser 100 is successively after the first chirp grating 221 and the second chirped fiber grating 222, the color of the first chirped fiber grating 221
Dissipate the chromatic dispersion compensation quantity that the sum of chromatic dispersion compensation quantity of compensation rate and the second chirped fiber grating 222 actually obtains for laser 100.
In the present embodiment, chirped fiber can be controlled by way of changing exposure power density I and time for exposure t
Variations in refractive index amplitude in grating.Refractive index n (I, t) and exposure power density I and time for exposure t has following relationship：
N (I, t)=AIatb(I)
Wherein A is 3.6 × 10-7, it is constant；A is 0.78, is constant；B is exposure intensity dependent coefficient, b (I)=0.165
+0.028exp(-I×1×10-5)。
As shown from the above formula, identical in time for exposure t, when exposure power density I ranging from 0~
600mW/cm2When, the variation of refractive index n (I, t) and the variation of exposure power density I are approximately linear, therefore change exposure work(
Rate density I can control the variation of the refractive index n (I, t) of optical fiber well.It is small to obtain refractive index n (I, t) in fiber grating
After difference, you can obtain different location bragg reflection wavelength λ in fiber gratingBFine difference, relationship meet：
λB=2neffΛ
Wherein neffFor optical fiber effective refractive index, Λ is screen periods.
Different location bragg reflection wavelength fine difference λB, indicate the same position in chirped fiber grating, meet anti-
The wavelength for penetrating condition has the reflection position of fine difference or the two-beam of identical frequency in chirped fiber grating with micro-
Small difference, the whole chromatic dispersion compensation quantity for considering as chirped fiber grating have fine difference.
The value of exposure power density I is set as 450mW/cm2When chromatic dispersion compensation quantity can be obtained is 14ps/nm dispersion measures
Fiber grating, and the setting value of exposure power density I is 440mW/cm2When can be obtained chromatic dispersion compensation quantity be 13.95ps/nm optical fiber
Grating.In actual use, by above-mentioned two fiber grating and optical fiber circulator Opposite direction connection, total dispersion compensation rate is two
The sum of chromatic dispersion compensation quantity of fiber grating, as 50fs/nm (i.e. 0.05ps/nm), therefore total dispersion compensation rate can reach fs/
The magnitude of nm compensates so as to the small dispersion measure to femtosecond laser.
Further, the absolute value of the total dispersion compensation rate of the first chirped fiber grating 21 and the second chirped fiber grating 22
Ranging from 50fs/nm~100fs/nm.Preferably, the absolute value of total dispersion compensation rate is 50fs/nm, so as to swash to femtosecond
The small dispersion measure of light compensates, the reliability of effective guarantee laser transmission.
Referring to Fig. 1, further, specimen inspection system 5 includes the photoconductive transmitting antenna for emitting THz wave
51, the photoconductive reception antenna 52 for receiving THz wave and the optical module 52 for being focused to THz wave, light
Conductance transmitting antenna 51 is connect with beam splitter 3, and photoconductive reception antenna 52 is connect with optical fibre drawing system 4 and photoconduction receives
Antenna 52 is connect with data processing system 7.Optical module 53 includes the THz wave for generating photoconductive transmitting antenna 51
The first lens group for focusing on detected sample 6 and for the THz wave after detected sample 56 to be focused on photoelectricity
Lead the second lens group of reception antenna 52.
Preferably, it is additionally provided with fiber delay line 54 between beam splitter 3 and photoconductive transmitting antenna 51.Current Terahertz
The delay line of time-domain spectroscopy instrument is free space delay line, and wherein most uses mobile platform into line delay.Such equipment
It deficient in stability and is easy vibrated and temperature fluctuation and delay is caused to be lacked of proper care.And fiber delay line is used in the present embodiment,
Stability is high, and is easily integrated.
In the present embodiment, optical module 53 includes four polyolefin lens, wherein the first lens group includes two polyenes
Hydrocarbon lens, the second lens group include other two polyolefin lens, and polyolefin lens can be aspherical mirror or spherical mirror, be used for
Collimation focusing is carried out to THz wave.The THz wave that photoconductive transmitting antenna 51 emits first passes around two of the first lens group
The surface of detected sample 6 is focused to after polyolefin lens, and test sample to be checked is carried after the surface reflection of detected sample 6
Then the information of product 6 is received after two polyolefin lens of the THz wave by the second lens group by photoconductive reception antenna 52,
And it is converted into corresponding electric signal.
Please refer to Fig. 8 and Fig. 9, traditional fiber stretcher uses piezoelectric ceramics stretching optical fiber, these piezoelectrics usually by
High-power high voltage source drives, and driver is of high cost, and high voltage power supply is also easy to interfere peripheral circuits, is unfavorable for equipment collection
At.Optical fibre drawing system 4 provided in this embodiment includes that 43, two optical fiber of the first coupler for being split to laser are drawn
Stretch device, the second coupler 44, the photodetector 45 for converting optical signals to electric signal for laser close beam
With the display device 46 for converting electrical signals to visualized graphs.Preferably, display device 46 is oscillograph, so as to
Convert electrical signals to visual time domain waveform.
For ease of description, two fiber stretchers are denoted as the first fiber stretcher 4101 and the second fiber stretcher respectively
4102.Beam splitter 3 is connect by optical fiber 10 with the first coupler 43, the first coupler 43 by optical fiber 10 simultaneously with the first light
Fine stretcher 4101, the connection of the second fiber stretcher 4102, the first fiber stretcher 4101, the second fiber stretcher 4102 pass through
Optical fiber 10 is connect with the second coupler 44, and the second coupler 44 is connect by optical fiber 10 with photodetector 45, photodetection
Device 45 is connect with display device 46.
Wherein, the optical fiber 10 being connect with the first fiber stretcher 4101 is wrapped in the appearance of the first fiber stretcher 4101
Face, the optical fiber 10 being connect with the second fiber stretcher 4102 are wrapped in the outer surface of the second fiber stretcher 4102.First optical fiber
One end where stretcher 4101 is reference arm, and one end where the second fiber stretcher 102 is then used as signal arm.
The operation principle of optical fibre drawing system 4 provided in this embodiment is as follows：
Laser is transferred to by optical fiber 10 at the first coupler；
Laser is divided into two beams, a branch of optical fiber by being wrapped in the first fiber stretcher 4101 after the first coupler 43
10 are transferred at the second coupler 44, and another beam is transferred to the second coupling by being wrapped in the optical fiber 10 of the second fiber stretcher 4102
At clutch 44；
The laser that two beams reach the second coupler 44 is merged into a branch of after the second coupler 44, and is passed by optical fiber 10
It is defeated to arrive at photoelectric sensor 45；
The optical signal received is changed into electric signal by photoelectric sensor 45, and electric signal is transmitted to display device 46
Place；
Display device 46 converts electrical signals to visualized graphs and is shown.
Specifically, the optical fiber 10 at the first fiber stretcher 4101 as reference arm and the second light as signal arm
When the tensile elongation of optical fiber 10 at fine stretcher 4102 is consistent, the light path that two beam laser are undergone is the same, therefore optical path difference is
Zero；Then, triangular modulation signal is applied to the second fiber stretcher 4102 as signal arm, so that by the second light
The light path for the laser that optical fiber 10 at fine stretcher 4102 transmits is transmitted with by the optical fiber 10 at the first fiber stretcher 4101
Laser light path it is different, to generate optical path difference；It is a branch of due to being merged into after two beam laser transfers to the second coupler, work as conjunction
Laser after and can interfere when being transferred at photoelectric sensor 45；By analyzing interference signal, you can obtain light
Path difference, to obtain the tensile elongation of optical fiber.
It should be understood that the first fiber stretcher 4101 is identical with the second fiber stretcher 4102, so as to have
Effect ensures when motor is in original state, optical fiber 10 is wrapped in the first fiber stretcher 4101 or the second optical fiber in an identical manner
When stretcher 4102, optical path difference zero.Using one end where the first fiber stretcher 4101 as with reference to arm, in order to
Solve the problems, such as that luminous effect intetference-fit strengthening caused by due to solderless wrapped connection is bent reduces.
Referring to Fig. 9, further, fiber stretcher includes telescopic rod 411, it is flexible that telescopic rod 411 can be driven to carry out
Motor 412 and pars contractilis 413 for winding optical fiber 10, one end of telescopic rod 411 are connect with motor 412, telescopic rod 411 it is another
One end connect with pars contractilis 413 and pars contractilis 413 can be driven to expand or shrink.
The operation principle of fiber stretcher is as follows：Motor 412 is fixed first, and by the one of motor 412 and telescopic rod 411
The other end of telescopic rod 411, then connect with pars contractilis 413, then optical fiber 10 is wrapped on pars contractilis 413 by end connection；
When needing to stretch optical fiber 10, motor 412 powers on, and driving telescopic rod 411 extends as needed, so as to band
Dynamic pars contractilis 413 is expanded, and then the optical fiber being wrapped on pars contractilis 413 10 can be driven to be stretched；When need not be to light
When fibre 10 is stretched, motor 412 drives telescopic rod 411 to bounce back, so as to drive pars contractilis 413 to be shunk, so that
The optical fiber 10 being wrapped on pars contractilis 413 is shunk.
The advantageous effect being arranged in this way is：Due to driving telescopic rod 411 to move using motor 412 and then driving flexible
The mode that portion 413 moves stretches optical fiber 10, so as to effectively increase the tensile elongation of optical fiber 10, and then can increase laser
Conveying length in optical fiber 10, to increase light path scanning range.
Further, pars contractilis 413 includes the first pars contractilis 4131 and the second pars contractilis 4132, and motor 412 is set to first
Between pars contractilis 4131 and the second pars contractilis 4132, and motor 412 is fixedly connected with the first pars contractilis 4131, telescopic rod 411
Between the first pars contractilis 4131 and the second pars contractilis 4132, and 411 other ends of telescopic rod and the second pars contractilis 4132 connect
It connects, optical fiber 10 is wrapped in the outer surface of the first pars contractilis 4131 and the second pars contractilis 4132.
When needing to stretch optical fiber 10, motor 412 drives telescopic rod 411 to extend, and telescopic rod 411 drives second to stretch
Contracting portion 4132 is moved to the direction far from the first pars contractilis 4131, is expanded outwardly so that pars contractilis 413 is whole, and then drive
The optical fiber 10 for being wrapped in 4132 surface of the first pars contractilis 4131 and the second pars contractilis is stretched；When need not be carried out to optical fiber 10
When stretching, motor 412 drives telescopic rod 411 to bounce back, so that the second pars contractilis 4132 is to close to the first pars contractilis 4131
Direction moves, and to 413 overall shrinkage of pars contractilis, and then drives and is wrapped in 4132 table of the first pars contractilis 4131 and the second pars contractilis
The optical fiber 10 in face is shunk.
Since pars contractilis 413 includes the first pars contractilis 4131 and the second pars contractilis 4132 that can be used relatively, to pass through
The relative motion of first pars contractilis 4131 and the second pars contractilis 4132 drives optical fiber 10 to be stretched and shunk, not only motion mode
Simple and flexible, and the tensile elongation of optical fiber 10 is easy to adjust, and can effectively increase the tensile elongation of optical fiber 10, increase light path
Scanning range.
Further, the first pars contractilis 4131 is the first semicylinder, and the surface of the first semicylinder winding optical fiber 10 is
Curved surface；Second pars contractilis 4132 is the second semicylinder, and the second surface for stretching semicylinder winding optical fiber 10 is curved surface.It is preferred that
Ground, the first pars contractilis 4131 and the second pars contractilis 4132 constitute a cylinder, and the first pars contractilis 4131 and the second pars contractilis
4132 sizes are identical.It is wrapped in due to optical fiber 10 on the curved surface of first semicylinder and the second semicylinder, optical fiber 10 exists
It is more smooth when stretching and shrinking, so that the stretching and contraction of optical fiber 10 are more natural and accurate, also prevent optical fiber 10
It is stretching and is being damaged in contraction process.
Preferably, the material of the first pars contractilis 4131 is metal, and the material of the second pars contractilis 4132 is metal.Therefore first
Pars contractilis 4131 and 4132 quality of the second pars contractilis are hard, can preferably drive optical fiber 10 to be stretched and shunk.It should be understood that
, the material of the first pars contractilis 4131 is alternatively the firm material of other quality, and the material of the second pars contractilis 4132 is alternatively
Other scleroid materials.
Further, the quantity of motor 412 is two, and the quantity of telescopic rod 411 mutually should be two, two 412 edges of motor
The axial alignment of first pars contractilis 4131 is fixed, and each motor 412 is all connected with a telescopic rod 411, two telescopic rods 411 it is another
One end is connect with the second pars contractilis 4132.Preferably, two electrodes 412 are respectively fixedly connected with close to the first pars contractilis 4131
Both ends position so that the first pars contractilis 4131 is more steady during the motion, so that the stretching of optical fiber 10
It is more steady with shrinking.
In the present embodiment, motor 412 is connected with motor driver, by controlling motor driver, to real
Now to the control of the motion mode of motor 412, and then fiber stretcher is controlled.Fiber stretcher is to being wrapped in pars contractilis
The maximum tension amount of optical fiber 10 on 413 is 6cm, so as to realize delay 200ps.
Referring to Fig. 10, further, locking phase amplification is additionally provided between photoconductive reception antenna 52 and DPA data processing activity 7
Module 8.Since the electrical signal energy converted by photoconductive reception antenna 52 is relatively low, it is therefore desirable to be amplified by current amplifier
Enter 8 two amplifications of locking phase amplification module afterwards, is then transferred to data processing system 7 again and is handled and analyzed.
For the bandwidth of compression noise, and signal-to-noise ratio is improved, needs to be amplified signal and Denoising disposal.Locking phase is put
Big module 8 has the characteristics that strong antijamming capability, signal accuracy are high in the small-signal in extracting very noisy, and can obtain
The variation of the size and Orientation of measured signal is taken, thus can be widely applied to signal detection.
Locking phase amplification module 8 includes signal path, reference channel, phase-sensitive detector 84 (being abbreviated as PSD) and low-pass filtering
Device 85.Signal path includes the lock-in amplifier 81 being connect with photoconductive reception antenna 52, and effect is first with noisy
The input signal amplification modulated with reference signal identical frequency, and put preliminary reduction noise through choosing.Reference channel includes successively
The square-wave signal source 82 and phase shifter 83 of connection, effect are to provide a reference signal with input signal same-phase, refer to
Signal is square-wave signal.Phase shifter 83 and lock-in amplifier 81 are connected with phase-sensitive detector 84, the effect of phase-sensitive detector 84
It is to be mixed to input signal and reference signal, output and frequency signal and difference frequency signal.Phase-sensitive detector 84 and low-pass filtering
Device 85 is connected, the effect of low-pass filter 85 be by with frequency target signal filter, only retain difference frequency signal.The difference frequency signal of reservation carries out
It is exported after enhanced processing.In the present embodiment, to realize the lock-in amplifier of inexpensive small size, using balance modem
Amplify into horizontal lock, to extract the faint terahertz signal flooded by noise, wide dynamic range reaches 100dB, can detect pA
The signal of grade.
Further, data processing system 7 includes data processing module 71 and the calculating that detected sample 6 is identified
Machine 72, data processing module 71 are connect by cable with computer 72, and data processing module 71 is connect with locking phase amplification module 8.
Further, data processing module 71 also has control action, can control each system of Terahertz detection device
The working condition of system.Specifically, data processing module 71 can control the working condition of laser system 1, to control
Whether laser system 1 starts to work.Data processing module 71 can control the motion state of motor 412 by motor driver,
To control the working condition of optical fibre drawing system 4.Data processing module 71 can be to the work shape of photoconductive transmitting antenna 51
State is controlled, to control whether photoconductive transmitting antenna 51 emits THz wave.Data processing module 71 can also simultaneously
The working condition of locking phase amplification module 8 is controlled.
Data processing module 71 extracts time domain electric field signal using equivalent sampling method, and is changed by optical fibre drawing system 4
Become the time delay between two laser pulses, high frequency, fast signal is changed into low frequency, slow speed signal is handled, to
Accurate reconstruction Terahertz waveform, realize terahertz signal it is effective acquisition and analysis and noise suppressed.
Although a transient current for being proportional to terahertz emission field can be obtained using photoconductive Detection Techniques, due to
Terahertz time-domain signal is about even shorter in picosecond (ps) magnitude, and current-responsive time rising edge is substantially all in subpicosecond amount
Grade, common current probe is difficult to measure the signal, it is therefore desirable to extract terahertz time-domain using equivalent time sampling technology
Electric field signal.Since laser pulse is femto-second laser pulse, the duration is much smaller than the duration of terahertz pulse, passes through
Change the time delay between two laser pulses, high frequency, fast signal can be changed into low frequency, slow speed signal processing,
Each period of repeating signal is separated by several periods and takes a sample, and each sample point is taken respectively from each waveform input signal
On different positions, several sample points form a cycle, can form the waveform similar to original signal a cycle, in turn
Terahertz waveform can be extracted.
Further, the combustible and explosive articles recognizer that computer 72 uses is reflective terahertz time-domain spectroscopy system
The recognizer of (being abbreviated as THz-TDS systems).
Common THz-TDS systems can be divided into two classes：Transmission-type and reflective.Passed through using transmission-type THz-TDS technologies
The transmission spectrum of each substance is measured, optical parameter is extracted, to which substance be identified.However use transmission-type THz-TDS skills
Two end in contact with substance are needed when art measures, and there is the liquid of very strong absorbent to liquid, particularly in terahertz wave band
Body, transmission-type THz-TDS technologies have great bottleneck on practicability and versatility.In contrast, using reflective THz-
When TDS technologies, due to THz wave only on container inner wall interface and liquid effects, without transmitted through liquid,
Superiority has been shown on the problem of liquid strong absorbent.
When detection is identified to different liquids using reflective THz-TDS technologies in tradition, during data processing
It needs time-domain signal to be transformed into frequency domain；However in practical applications since chamber wall is often very thin, reference signal and detection are believed
Number close proximity so that data processing is difficult, therefore this method practical level is not high, does not adapt to the container or packet of different-thickness
Dress.
Terahertz detection device provided in this embodiment utilizes the refractive index difference of different material, so as to cause detection signal
The different characteristic of amplitude and shape of light pulse utilizes the method pair of pattern-recognition for the detection signal pulse of time domain
Article components in container or packaging are differentiated.
The process of the combustible and explosive articles recognizer of Terahertz detection device provided in this embodiment is：
Data Dimensionality Reduction is carried out first with principal component analysis, realizes the feature extraction of data；
Using intelligent algorithm (such as linear discriminant analysis or algorithm of support vector machine design can be used), article is pacified
Differentiated whether complete.
It is analyzed again due to being not necessarily to carry out Fourier transformation to be transformed into frequency domain, thus the time of substance differentiation can be reduced.
1 and Figure 12 are please referred to Fig.1, for detecting beverage ingredient, illustrates that the present embodiment utilizes terahertz time-domain spectroscopy skill
Art dangerous material know method for distinguishing.When terahertz pulse 611 is propagated in air, liquid bottles 602 and liquid 601, respectively in air
Two secondary reflections occur with 603 contact position of bottle outer wall, bottle inner wall 604 and 601 contact position of liquid.The fresnel formula of reflectivity is：
Wherein n1、n2For the refractive index for two kinds of materials being in contact, the angles θ are incidence angle.
Terahertz pulse 611 is measured for the first time to propagate in air, liquid bottles 602 and Air Interface, can obtain first
Reflected impulse 612, so as to measure liquid bottles 602 material dielectric constant and thickness；When obtaining the material of liquid bottles 602
After expecting parameter, then can once obtain in the measurement at 601 interface of air, the bottle inner wall 604 of liquid bottles 602 and liquid the
Two reflected impulses 613, by the dielectric constant that can obtain liquid 601 after data processing.
Different liquid 601 is reflecting terahertz pulse of different shapes.The reflected impulse shape of different liquids is carried out
Principal component analysis, is calculated its cumulative variance value, and cumulative variance formula is as follows：
Wherein, N is the quantity that calibration sample concentrates sample,It is i-th of reference value of sample,It is i-th of sample
Predicted value.Threshold decision is carried out to cumulative variance value, is then dangerous material more than threshold value.
The above description is only the embodiments of the present invention, is not intended to limit the utility model, all in this practicality
All any modification, equivalent and improvement etc., should be included in the guarantor of the utility model made by within novel spirit and principle
Within the scope of shield.
Claims (10)
1. a kind of Terahertz detection device, it is characterised in that：Include for generating the laser system of laser, for the laser
Carry out the Dispersion Compensation Systems of dispersion compensation, beam splitter, the optical fibre drawing system for carrying out delayed sweep to the laser,
Specimen inspection system for generating and receiving THz wave and be detected to detected sample and for test data into
The data processing system of row analysis, the laser system are connect by optical fiber with the Dispersion Compensation Systems, the dispersion compensation
System is connect by optical fiber with the beam splitter, the beam splitter by optical fiber simultaneously with the optical fibre drawing system, institute
Specimen inspection system connection is stated, the optical fibre drawing system is connect by optical fiber with the specimen inspection system, while the sample
Product examine examining system is connect with the data processing system.
2. Terahertz detection device as described in claim 1, it is characterised in that：The laser system includes sequentially connected sharp
Light device, saturable absorber, photo-coupler, gain fibre and fiber grating, the photo-coupler and the saturable absorber
The side of connection is also associated with pumping source.
3. Terahertz detection device as claimed in claim 2, it is characterised in that：The laser system further includes repetition rate lock
Determine mechanism, the repetition rate locking mechanism is used to lock the frequency for the laser that the laser generates, and the laser is equipped with
It can be used for adjusting the piezoelectric ceramics of the chamber length of its laser cavity, the repetition rate locking mechanism is connect with the piezoelectric ceramics, together
Shi Suoshu repetition rates locking mechanism is connect with the laser.
4. Terahertz detection device as claimed in claim 3, it is characterised in that：The repetition rate locking mechanism includes successively
Photodetector, bandpass filter, frequency mixer, loop filter and the high-voltage amplifier of connection, the photodetector and institute
It states laser to be connected, the high-voltage amplifier is connect with the piezoelectric ceramics, and the frequency mixer connects the bandpass filter
Side is also associated with reference generator, and the reference generator is locked on rubidium clock.
5. Terahertz detection device as described in claim 1, it is characterised in that：The Dispersion Compensation Systems include for adjusting
The fiber annular mechanism of the laser transmission direction, it is opposite for carrying out dispersion compensation and chromatic dispersion compensation quantity to the laser
First chirped fiber grating and the second chirped fiber grating, the fiber annular mechanism are equipped with the input for being connect with optical fiber
End, the optical fiber are used for transmission the laser, and first chirped fiber grating and second chirped fiber grating are and institute
The connection of fiber annular mechanism is stated, and the laser passes sequentially through first chirped fiber grating and the second chirped fiber light
It is emitted from the fiber annular mechanism after grid, the dispersion of first chirped fiber grating and second chirped fiber grating
The absolute value of compensation rate is unequal.
6. Terahertz detection device as described in claim 1, it is characterised in that：The specimen inspection system includes for generating
The photoconductive transmitting antenna of THz wave, the photoconductive reception antenna for receiving the THz wave and for the terahertz
The optical module that hereby wave is focused, the photoconduction transmitting antenna are connect with the beam splitter, and the photoconduction receives day
Line is connect with the optical fibre drawing system and the photoconductive reception antenna is connect with the data processing system.
7. Terahertz detection device as claimed in claim 6, it is characterised in that：The optical module includes for by the light
The first lens group and be used to pass through described that the THz wave that conductance transmitting antenna generates focuses on the detected sample
THz wave after detected sample focuses on the second lens group of the photoconductive reception antenna.
8. Terahertz detection device as claimed in claim 6, it is characterised in that：The optical fibre drawing system includes for swashing
The first coupler that light is split, two fiber stretchers, the second coupler for laser close beam, for by light
Signal is converted to the photodetector of electric signal and the display device for converting electrical signals to visualized graphs, the light point
Beam device is connect with first coupler by optical fiber, and first coupler passes through light with two fiber stretchers simultaneously
Fibre connection, two fiber stretchers are connect with second coupler by optical fiber, second coupler with it is described
Photodetector is connected by optical fiber, and the photodetector is connect with the display device.
9. Terahertz detection device as claimed in claim 6, it is characterised in that：The photoconduction reception antenna and the data
Locking phase amplification module is additionally provided between processing system.
10. Terahertz detection device as claimed in claim 9, it is characterised in that：The data processing system includes at data
Reason module and the computer that the detected sample is identified, the data processing module pass through cable and the computer
Connection, the data processing module are connect with the locking phase amplification module.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019183953A1 (en) * | 2018-03-30 | 2019-10-03 | 深圳市华讯方舟太赫兹科技有限公司 | Optic fiber stretching device and optic fiber delayed scanning system |
| CN113655024A (en) * | 2021-09-29 | 2021-11-16 | 岭澳核电有限公司 | Visual terahertz time-domain spectroscopy detection device, detection method and application |
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2018
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019183953A1 (en) * | 2018-03-30 | 2019-10-03 | 深圳市华讯方舟太赫兹科技有限公司 | Optic fiber stretching device and optic fiber delayed scanning system |
| CN113655024A (en) * | 2021-09-29 | 2021-11-16 | 岭澳核电有限公司 | Visual terahertz time-domain spectroscopy detection device, detection method and application |
| CN113655024B (en) * | 2021-09-29 | 2023-07-14 | 岭澳核电有限公司 | Visual terahertz time-domain spectrum detection device, detection method and application |
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