CN109696422A - Terahertz Near-Field Radar Imaging device and method - Google Patents
Terahertz Near-Field Radar Imaging device and method Download PDFInfo
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- CN109696422A CN109696422A CN201811612958.0A CN201811612958A CN109696422A CN 109696422 A CN109696422 A CN 109696422A CN 201811612958 A CN201811612958 A CN 201811612958A CN 109696422 A CN109696422 A CN 109696422A
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- 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
- G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
Abstract
The invention relates to a kind of Terahertz Near-Field Radar Imaging device and method, Terahertz Near-Field Radar Imaging device includes terahertz light source module, for emitting thz laser；Beam splitter, for thz laser to be divided into signal light and reference light；Reflecting module, including probe unit and reflector element, probe unit are arranged on the optical axis of the transmission of signal light, for receiving signal light and by signal light emitting to sample, to excite sample feedback to carry the reflected light of sample message；Reflector element is arranged on the optical axis of reference optical transport, for receiving simultaneously reflected reference light；Beam splitter is also used to receive reflected light and reference light, to form the Terahertz interference light signal of reflected light and reference light；Processing module, for handling Terahertz interference light signal, to obtain the image information of sample.The device is interfered by being emitted signal light by probe unit to sample, and by the reflected light that the reference light that reflector element reflects is fed back with sample, Terahertz Near-Field Radar Imaging may be implemented, and resolution ratio is higher.
Description
Technical field
This application involves THz imaging technology fields, more particularly to a kind of Terahertz Near-Field Radar Imaging device and method.
Background technique
Terahertz refers to frequency in the electromagnetic wave of 0.1 to 10 Terahertz frequency range, is between millimeter wave and infrared light
Electromagnetic wave has the characteristics that safety, broadband property, " fingerprint spectral property " and penetrability.THz wave can penetrate a variety of insulation
Material and be a kind of Non-ionizing radiation, may be implemented the lossless harmless detection to human body or article.Terahertz signal it is above-mentioned
Advantage makes Terahertz near-field imaging technique have various application demands, such as safety check security protection, the identification of chemicals, medicine
Imaging, quality control etc..Traditionally, the resolution ratio of Terahertz Near-Field Radar Imaging is lower.
Summary of the invention
The application provides a kind of Terahertz Near-Field Radar Imaging device and method, and the resolution of Terahertz Near-Field Radar Imaging can be improved
Rate.
A kind of Terahertz Near-Field Radar Imaging device, comprising:
Terahertz light source module, for emitting thz laser；
Beam splitter is arranged on the optical axis of the thz laser transmission, for the thz laser to be divided into signal
Light and reference light；
The light of the signal optical transport is arranged in reflecting module, including probe unit and reflector element, the probe unit
On axis, for receiving the signal light and by the signal light emitting to sample, to excite the sample feedback to carry sample letter
The reflected light of breath；The reflector element is arranged on the optical axis with reference to optical transport, for receiving and reflecting the reference light；
The beam splitter is also used to receive the reflected light and the reference light, to form the reflected light and the reference
The Terahertz interference light signal of light；
Processing module, for receiving the Terahertz interference light signal, and to the Terahertz interference light signal at
Reason, to obtain the image information of the sample.
In one embodiment, the processing module includes:
Detector turns for receiving and detecting the Terahertz interference light signal, and by the Terahertz interference light signal
It is changed to electric signal；
Processor carries out digitized processing for receiving the electric signal, and to the electric signal, to obtain the sample
Image information.
In one embodiment, the needle point of the probe unit is metal needle point, and the radius of the metal needle point is 10-
50 nanometers.
In one embodiment, the metal needle point is nanometer scale at a distance from the sample.
In one embodiment, described device further includes multiple reflecting mirrors, is arranged on the optical axis of the signal optical transport,
For changing the outgoing route of the signal light, by the signal light emitting to the probe unit.
In one embodiment, described device further includes collimation lens, setting the detector and the beam splitter it
Between, for carrying out collimation processing to the Terahertz interference light signal.
In one embodiment, described device further include:
Example platform, for placing the sample；
The processing module is also connect with the example platform, mobile to drive the sample for controlling the example platform
Product are mobile, so that different location of the signal light emitting to the sample.
In one embodiment, the detector is Schottky diode.
In one embodiment, the terahertz light source module be Terahertz gas laser or it is Terahertz quantum cascaded swash
Light device.
A kind of Terahertz Near-Field Radar Imaging method is based on Terahertz Near-Field Radar Imaging device, the Terahertz Near-Field Radar Imaging device
It include: terahertz light source module, beam splitter, reflecting module and processing module；The described method includes:
It controls terahertz light source module and emits thz laser；
The thz laser is divided into signal light and reference light；
Control reflecting module receives the signal light and by the signal light emitting to sample, to excite the sample to feed back
Carry the reflected light of sample message；It receives and reflects the reference light；
The reflected light and the reference light are received, to form the Terahertz interference light of the reflected light and the reference light
Signal；
Control processing module and receive the Terahertz interference light signal, and to the Terahertz interference light signal at
Reason, to obtain the image information of the sample.
Above-mentioned Terahertz Near-Field Radar Imaging device, comprising: terahertz light source module, for emitting thz laser；Beam splitter,
It is arranged on the optical axis of the thz laser transmission, for the thz laser to be divided into signal light and reference light；Reflection
Module, including probe unit and reflector element, the probe unit is arranged on the optical axis of the signal optical transport, for receiving
The signal light and by the signal light emitting to sample, to excite the sample feedback to carry the reflected light of sample message；Institute
It states reflector element to be arranged on the optical axis with reference to optical transport, for receiving and reflecting the reference light；The beam splitter is also
For receiving the reflected light and the reference light, to form the Terahertz interference light letter of the reflected light and the reference light
Number；Processing module is handled for receiving the Terahertz interference light signal, and to the Terahertz interference light signal, with
Obtain the image information of the sample.The device by probe unit by being emitted signal light to sample, to realize that near field is visited
It surveys, and is interfered by the reflected light that the reference light that reflector element reflects is fed back with sample, to form interference signal, so as to
To realize Terahertz Near-Field Radar Imaging, and resolution ratio is higher.
Detailed description of the invention
In order to illustrate the technical solutions in the embodiments of the present application or in the prior art more clearly, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of application for those of ordinary skill in the art without creative efforts, can be with
It obtains other drawings based on these drawings.
Fig. 1 is the structural schematic diagram of the Terahertz Near-Field Radar Imaging device provided in one embodiment；
Fig. 2 is the flow chart of the Terahertz Near-Field Radar Imaging method provided in one embodiment.
In order to illustrate the technical solutions in the embodiments of the present application or in the prior art more clearly, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of application for those of ordinary skill in the art without creative efforts, can be with
It obtains other drawings based on these drawings.
Specific embodiment
The application in order to facilitate understanding, in order to make the above objects, features, and advantages of the present application more apparent, under
Face is described in detail in conjunction with specific embodiment of the attached drawing to the application.It is explained in the following description many details
In order to fully understand the application, the better embodiment of the application is given in attached drawing.But the application can be with many not
With form realize, however it is not limited to embodiments described herein.On the contrary, the purpose of providing these embodiments is that making
Disclosure of this application is understood more thorough and comprehensive.The application can be to be much different from other way described herein
Implement, those skilled in the art can do similar improvement without prejudice to the application intension, therefore the application not by
The limitation of following public specific embodiment.
Unless otherwise defined, all technical and scientific terms used herein and the technical field for belonging to the application
The normally understood meaning of technical staff is identical.Term used herein is intended merely to the mesh of description specific embodiment
, it is not intended that in limitation the application.Term " and or " used herein includes one or more relevant listed items
Any and all combinations.
Fig. 1 is the structural schematic diagram for the Terahertz Near-Field Radar Imaging device that an embodiment provides, as shown in Figure 1, Terahertz is close
Field imaging device 100, including terahertz light source module 110, beam splitter 120, reflecting module 130 and processing module 140, in which:
Terahertz light source module 110, for emitting thz laser.Terahertz light source module 110 can be Terahertz gas
Body laser or Terahertz quantum cascaded laser.
In one embodiment, terahertz light source module 110 may include that a Terahertz quantum cascaded laser and one connect
Connect the laser power supply of Terahertz quantum cascaded laser.Wherein, Terahertz quantum cascaded laser swashs for emitting Terahertz
Light, Terahertz quantum cascaded laser can produce high power terahertz emission, be conducive to the detection of terahertz signal.Laser electricity
Source is used to provide pulsed bias to Terahertz quantum cascaded laser, and Terahertz quantum cascaded laser is made to be in continuous
Wave operating mode.
In the present embodiment, the dynamic range of THz wave laser caused by terahertz light source module 110 can be 3000
More than, spectrum width is 0.1 to 3.0THz, so as to have so that signal obtains the signal-to-noise ratio at time domain peak greater than 30dB
The frequency spectrum resolution capability of 10GHz or more.
Beam splitter 120 is arranged on the optical axis of the transmission of thz laser, for by thz laser be divided into signal light and
Reference light.
The thz laser received can be divided into signal light and ginseng after receiving thz laser by beam splitter 120
Two beam laser of light is examined, and by signal light and with reference to light emitting to transmitting module 130.Wherein, metal can be set on beam splitter 120
Film or deielectric-coating.
In one embodiment, reflecting module 130 includes probe unit 131 and reflector element 132, and probe unit 131 is arranged
On the optical axis of the transmission of signal light, for receiving signal light and by signal light emitting to sample, to excite sample feedback to carry
The reflected light of sample message；Reflector element 132 is arranged on the optical axis of reference optical transport, for receiving simultaneously reflected reference light.
In one embodiment, probe unit 131 is arranged on the signal optical transport optical axis of the transmitting of beam splitter 120, is receiving
By signal light emitting to sample after to signal light, since sample generates the reflection of carrying sample message to the absorption of signal light
Light.The amplitude and phase information of reflected light can reflect out sample message.Specifically, probe unit 131 receive signal light it
After can be by optic path module 150 by signal light emitting to probe unit 131.
In one embodiment, probe unit 131 may include the detection needle point of atomic force microscope.
The needle point of probe unit 131 is metal needle point, and the radius of metal needle point is 10-50 nanometers.Thz laser hair
It is incident upon at the metal needle point of probe unit 131, tip end can form the Terahertz hot spot of annular spread.In addition, by sample
It is fixed in tip end near-field region through two-dimentional electronic control translation stage, near-field region can be metal needle point and be at a distance from sample
Nanometer scale.Point by point scanning is carried out by metal needle point, to realize super-resolution imaging.Wherein super-resolution imaging is nanometer amount
Grade, the super-resolution imaging of a ten thousandth wavelength.The resolution ratio of super-resolution imaging depends on tip dimensions and scanning step-wise displacement, needle
Point is higher more the resolution ratio for being fine into picture.The radius of the metal needle point of the embodiment of the present application is 10-50 nanometers, and imaging can be improved
Resolution ratio.
Specifically, thz laser can be in its surface phasmon of 131 surface excitation of probe unit, and along probe list
Member 131 is propagated.The metal needle point radius of probe unit 131 is nanometer scale, and thz laser is in the form of surface phasmon
Metal needle point end is propagated to, longer wavelengths of thz laser is with the formal constraint of surface phasmon in metal needle at this time
Sharp end, forms the Terahertz hot spot of an annular spread having a size of nanometer scale, which is much smaller than the wavelength of Terahertz
Size.Since thz laser leaves, the angle of divergence after metal needle point end is radiated into air is huge, and hot spot diverging is serious, therefore will
Sample is placed in the near-field region much smaller than wavelength dimension, and Near-Field Radar Imaging may be implemented.By guaranteeing the condition of Near-Field Radar Imaging,
The super-resolution imaging of THz wave can be realized.
It should be noted that Terahertz surface plasmons is only propagated on the surface of probe unit 131, so
The hot spot that metal needle point end is formed is annular spread, and decays and dissipate rapidly to free space, so to realize optimal
The super-resolution imaging of change, the distance between needle point and sample to be imaged must satisfy Near Field.
In one embodiment, measuring for verticality can be set in the needle point of probe unit 131 and the near-field region of sample
Module (not shown) and distance of near field feedback module (not shown), for adjust needle point and sample verticality and
Distance simultaneously provides feedback information in real time, to guarantee the condition of Near-Field Radar Imaging.
In one embodiment, optic path module 150 may include multiple reflecting mirrors, and the optical axis of signal optical transport is arranged in
On, for changing the outgoing route of signal light, by signal light emitting to probe unit 131.
Reflecting mirror may include plane mirror 151, lens 152, paraboloidal mirror 153.The signal light of beam splitter transmitting is first
First emit to plane mirror 151, reflexes to lens 152 through plane mirror 151, lens 152 emit plane mirror 151
Signal light carry out signal light emitting to paraboloidal mirror 152 after collimation processing again, spy is arranged by signal light is counter in paraboloidal mirror 153
Needle unit 131.
In one embodiment, the optical axis of the reference optical transport emitted in beam splitter 120 can be set in reflector element 132
On, for receiving simultaneously reflected reference light, to change the relative delay of signal light and reference light.Specifically reflector element 132
It can be delayer, delay line, interferential scanning instrument etc..
The reference light that beam splitter 120 is also used to receive the reflected light of the reflection of probe unit 131 and reflector element 132 reflects,
To form the Terahertz interference light signal of reflected light and reference light.
Specifically, reflected light and reference light are that two-way frequency is identical and optical signal with fixed skew, two paths of signals
It can be in identical Propagation.Before two paths of signals meets, reflected light and reference light are not interfere with each other；When meeting, reflection
Light and refer to optical superposition, reinforces the vibration of some regions, the vibration weakening of some regions, and vibrate reinforcement region and vibration
The dynamic region weakened is spaced from each other, to form Terahertz interference light signal.Terahertz interference light signal be formed by pattern
Interference pattern is made, interference pattern carries the information of sample.In this process, it is best can to find interference for reflector element 132
Light path point, so that signal light and reference light interfere at beam splitter 120.Generally reflector element 132 is apart from beam splitter 120
Several microns to 200 microns.
Processing module 140 is handled for receiving Terahertz interference light signal, and to Terahertz interference light signal, with
Obtain the image information of the sample.Specifically, processing module 140 can frequency, phase according to Terahertz interference light signal
The image information of sample is obtained with amplitude.
In one embodiment, processing module may include detector 141 and processor 142, wherein
Terahertz interference light signal is converted to electricity for receiving and detecting Terahertz interference light signal by detector 141
Signal.Processor 142 carries out digitized processing for receiving electric signal, and to the electric signal, to obtain the figure of the sample
As information.
Wherein, detector 141 can be the cooling low-temperature superconducting bolometer of Golay detector, pyroelectric detector, liquid helium,
Schottky diode, photoconductivity switching or electro-optic crystal etc..
In one embodiment, detector 141 is Schottky diode.It is dry that Terahertz is not received in Schottky diode
Original state when relating to optical signal, in breakdown under the action of bias voltage；It is dry that Terahertz is received in Schottky diode
When relating to optical signal, Terahertz interference light signal is converted to detectable electric signal by Schottky diode, and by the electric signal
It is changed into voltage signal so as to export transient current pulse signal.Schottky diode wave detector can by silicon, GaAs,
Other compound semiconductor materials such as gallium nitride or silicon carbide are made.Terahertz interference light signal can be directly incident on Xiao Te
On based diode.The detectivity of Schottky diode is higher, therefore interferes by using Schottky diode Terahertz
Optical signal is detected, and can promote Effect on Detecting, and then promote image quality.
In one embodiment, processor 142 can be computer, can be equipped with image processing software on computer, can
To carry out digitized processing to electric signal by image processing software, to obtain the image information of sample, and according to image information
Show sample image.
Specifically, processor 142 may include data processing unit and image restoring unit.It can pacify on processor 142
Equipped with labview and matlab software, it is possible thereby to pass through labview and matlab software realization synchronously control data processing list
The execution of member and image restoring unit simultaneously realizes imaging.
In one embodiment, Terahertz Near-Field Radar Imaging device 100 further includes collimation lens 160, is arranged in detector 141
Between beam splitter 120, for carrying out collimation processing to Terahertz interference light signal.So that Terahertz interference light signal passes through standard
After straight lens 160 collimate, then emit to detector 141, to improve the collection efficiency of Terahertz interference light signal.
Above-mentioned Terahertz Near-Field Radar Imaging device 100, comprising: terahertz light source module 110, for emitting thz laser；
Beam splitter 120 is arranged on the optical axis of the transmission of the thz laser, for by the thz laser be divided into signal light and
Reference light；The biography of signal light is arranged in reflecting module 130, including probe unit 131 and reflector element 132, the probe unit
On defeated optical axis, for receiving signal light and by signal light emitting to sample, to excite sample feedback to carry the anti-of sample message
Penetrate light；Reflector element 131 is arranged on the optical axis of reference optical transport, for receiving simultaneously reflected reference light；Beam splitter 120 is also used to
Reflected light and reference light are received, to form the Terahertz interference light signal of reflected light and reference light；Processing module 140, for connecing
Terahertz interference light signal is received, and the Terahertz interference light signal is handled, to obtain the image information of sample.The dress
It sets by being emitted signal light by probe unit to sample, to realize that near field detects, and the reference reflected by reflector element
The reflected light that light is fed back with sample is interfered, and to form interference signal, so as to realize Terahertz Near-Field Radar Imaging, and is differentiated
Rate is higher.
In one embodiment, Terahertz Near-Field Radar Imaging device 100 further include:
Example platform, for placing sample；
Processing module 140 is also connect with example platform, mobile to drive sample mobile for controlling example platform, so that letter
Number light emitting to sample different location.
It is mobile that processing module 140 can control example platform, and obtains after being moved to a position and record the position
Coordinate information, and the coordinate information is sent to processor 140.
In one embodiment, data processing unit uses driving of the labview software realization to controller, current to obtain
The coordinate information of the corresponding Sample Scan point of received electric signal.Image restoring unit is by matlab program pin to processing module
The corresponding electric signal sent of coordinate information and detector 141 of the 140 each scanning elements sent and progress data processing, with reduction
It sample image and is shown out.
Sample can be fixed in the tip end distance of near field of probe unit 131 via electronic control translation stage, by point-by-point
Scanning, the corresponding electric signal of Terahertz interference signal of available each scanning element of sample surfaces of detector 141, via place
Reason module 140 is handled, and can obtain the sample in the super-resolution imaging of terahertz wave band.
Fig. 2 is the flow chart for the Terahertz Near-Field Radar Imaging method that an embodiment provides.As shown in Fig. 2, a kind of Terahertz is close
Field imaging method, is based on Terahertz Near-Field Radar Imaging device, Terahertz Near-Field Radar Imaging device includes: terahertz light source module, beam splitting
Device, reflecting module and processing module；It is characterized in that, the Terahertz Near-Field Radar Imaging method includes: step 210 to step 250.
Step 210, control terahertz light source module emits thz laser；Terahertz light source module can be Terahertz gas
Body laser or Terahertz quantum cascaded laser.
In one embodiment, terahertz light source module may include a Terahertz quantum cascaded laser and a connection
The laser power supply of Terahertz quantum cascaded laser.Wherein, Terahertz quantum cascaded laser is used to emit thz laser,
Terahertz quantum cascaded laser can produce high power terahertz emission, be conducive to the detection of terahertz signal；Laser power supply
For providing pulsed bias to Terahertz quantum cascaded laser, and Terahertz quantum cascaded laser is made to be in continuous wave
Operating mode.
In the present embodiment, the dynamic range of THz wave laser caused by terahertz light source module can 3000 with
On, spectrum width is 0.1 to 3.0THz, so as to have 10GHz so that signal obtains the signal-to-noise ratio at time domain peak greater than 30dB
Above frequency spectrum resolution capability.
Step 220, the thz laser is divided into signal light and reference light by control beam splitter；
The thz laser received can be divided into signal light and reference light after receiving thz laser by beam splitter
Two beam laser.Wherein, metal film or deielectric-coating can be set on beam splitter.
Step 230, control reflecting module receives signal light and by signal light emitting to sample, to excite sample feedback to carry
The reflected light of sample message；Also control reflecting module receives and reflects the reference light；
In one embodiment, reflecting module includes probe unit and reflector element, and the biography of signal light is arranged in probe unit
On defeated optical axis, for receiving the signal light and by the signal light emitting to sample, to excite sample feedback to carry sample
The reflected light of information；Reflector element is arranged on the optical axis of reference optical transport, for receiving and reflecting the reference light.
Probe unit is arranged on the transmission optical axis of the signal light of beam splitter transmitting, by signal after receiving signal light
Light emitting is to sample, since sample generates the reflected light of carrying sample message to the absorption of signal light.The amplitude of reflected light and
Phase information can reflect out sample message.Specifically, probe unit can be by optic path mould after receiving signal light
Block is by signal light emitting to probe unit, wherein optic path module may include multiple reflecting mirrors, be arranged in signal optical transport
Optical axis on, for changing the outgoing route of signal light, by signal light emitting to probe unit.
In one embodiment, probe unit may include that atomic force microscope obtains probe tip.
In one embodiment, the needle point of probe unit is metal needle point, and the radius of metal needle point is 10-50 nanometers.
Thz laser emits to the metal needle point of probe unit, and tip end can form the Terahertz hot spot of annular spread.Separately
Outside, sample is fixed in tip end near-field region through two-dimentional electronic control translation stage, near-field region can be metal needle point and sample
The distance of product is nanometer scale.Point by point scanning is carried out by metal needle point, to realize super-resolution imaging.Wherein super-resolution imaging
For nanometer scale, the super-resolution imaging of a ten thousandth wavelength.The resolution ratio of super-resolution imaging depends on tip dimensions and scanning step
Carry is moved, and needle point is higher more the resolution ratio for being fine into picture.The radius of the metal needle point of the embodiment of the present application is 10-50 nanometers, can be with
Improve the resolution ratio of imaging.
Specifically, thz laser can be in its surface plasmons of probe unit surface excitation, and along probe list
Member is propagated.The metal needle point radius of probe unit is nanometer scale, and thz laser is propagated in the form of surface phasmon
Metal needle point end, longer wavelengths of thz laser is with the formal constraint of surface phasmon in metal needle point end at this time
End, forms the Terahertz hot spot of an annular spread having a size of nanometer scale, which is much smaller than the wavelength dimension of Terahertz.
Radiate that the angle of divergence into after in air is huge, and hot spot diverging is serious since thz laser leaves metal needle point end, therefore by sample
It is placed in the near-field region much smaller than wavelength dimension, Near-Field Radar Imaging may be implemented.By the condition for guaranteeing Near-Field Radar Imaging
Realize the super-resolution imaging of THz wave.
It should be noted that Terahertz surface phasmon is only propagated on the surface of probe unit, so in metal
The hot spot that tip end is formed is annular spread, and decays and dissipate rapidly to free space, so to realize optimization
Super-resolution imaging, the distance between needle point and sample to be imaged must satisfy Near Field.
In one embodiment, measuring for verticality module can be set in the needle point of probe unit and the near-field region of sample
(not shown) and distance of near field feedback module (not shown), for adjusting the verticality and distance of needle point and sample
And feedback information is provided in real time, to guarantee the condition of Near-Field Radar Imaging.
In one embodiment, reflecting mirror may include plane mirror, lens, paraboloidal mirror etc..Beam splitter transmitting
Signal light emits first to plane mirror, reflexes to lens through plane mirror, the signal light that lens emit reflecting mirror into
Again by signal light emitting to paraboloidal mirror after the processing of row collimation, probe unit is arranged by signal light is counter in paraboloidal mirror.
In one embodiment, reflector element is arranged on the optical axis of the reference optical transport of beam splitter transmitting, for receiving
And reflected reference light, to change the relative delay of signal light and reference light.Specifically reflector element 132 can be delay
Device, delay line, interferential scanning instrument etc..
Step 240, control beam splitter receives reflected light and reference light, to form the Terahertz interference of reflected light and reference light
Optical signal；
Beam splitter is also used to receive the reflected light of probe unit reflection and the reference light of reflector element reflection, to form reflection
The Terahertz interference light signal of light and reference light.
Specifically, reflected light and reference light are that two-way frequency is identical and optical signal with fixed skew, two paths of signals
It can be in identical Propagation.Before two paths of signals meets, reflected light and reference light are not interfere with each other；When meeting, reflection
Light and refer to optical superposition, reinforces the vibration of some regions, the vibration weakening of some regions, and vibrate reinforcement region and vibration
The dynamic region weakened is spaced from each other, to form Terahertz interference light signal.Terahertz interference light signal be formed by pattern
Interference pattern is made, interference pattern carries the information of sample.In this process, reflector element, which can be found, interferes best light path
Point, so that signal light and reference light interfere at beam splitter 120.General reflector element is several microns apart from beam splitter and arrives
200 microns.
Step 250, control processing module receives the Terahertz interference light signal, and to the Terahertz interference light signal
It is handled, to obtain the image information of the sample.
Specifically, processing module can obtain sample according to the frequency of Terahertz interference light signal, phase and amplitude
Image information.
In one embodiment, processing module may include detector and processor, wherein
Terahertz interference light signal is converted to telecommunications for receiving and detecting Terahertz interference light signal by detector
Number.Processor carries out digitized processing for receiving electric signal, and to the electric signal, to obtain the image letter of the sample
Breath.Detector can be the cooling low-temperature superconducting bolometer of Golay detector, pyroelectric detector, liquid helium, Schottky diode,
Photoconductivity switching or electro-optic crystal etc..
In one embodiment, detector is Schottky diode.It is dry that Terahertz is not received by Schottky diode
Original state when relating to optical signal, in breakdown under the action of bias voltage；It is dry that Terahertz is received in Schottky diode
When relating to optical signal, Terahertz interference light signal is converted to detectable electric signal by Schottky diode, and by the electric signal
It is changed into voltage signal so as to export transient current pulse signal.Schottky diode wave detector can by silicon, GaAs,
Other compound semiconductor materials such as gallium nitride or silicon carbide are made.Terahertz interference light signal can be directly incident on Xiao Te
On based diode.The detectivity of Schottky diode is higher, therefore interferes by using Schottky diode Terahertz
Optical signal is detected, and can promote Effect on Detecting, and then promote image quality.
In one embodiment, processor can be computer, can be equipped with image processing software, Ke Yitong on computer
It crosses image processing software and digitized processing is carried out to electric signal, to obtain the image information of sample, and according to image information display
Sample image out.
Specifically, processor may include data processing unit and image restoring unit.It can be equipped on processor
Labview and matlab software, it is possible thereby to by labview and matlab software realization synchronously control data processing unit with
The execution of image restoring unit simultaneously realizes imaging.
In one embodiment, Terahertz Near-Field Radar Imaging device further includes collimation lens, is arranged in detector and beam splitter
Between, for carrying out collimation processing to Terahertz interference light signal.So that Terahertz interference light signal is collimated by collimation lens
Afterwards, then emit to detector, to improve the collection efficiency of Terahertz interference light signal.
Above-mentioned imaging method, comprising: control terahertz light source module emits thz laser；It is described too to control beam splitter general
Hertz laser is divided into signal light and reference light；It controls reflecting module and receives the signal light and by the signal light emitting to sample
Product, to excite the sample feedback to carry the reflected light of sample message；It receives and reflects the reference light；Beam splitter is controlled to receive
The reflected light and the reference light, to form the Terahertz interference light signal of the reflected light and the reference light；At control
It manages module and receives the Terahertz interference light signal, and the Terahertz interference light signal is handled, to obtain the sample
The image information of product.Above-mentioned imaging method by probe unit by being emitted signal light to sample, to realize that near field detects, and
Interfered by the reflected light that the reference light that reflector element reflects is fed back with sample, to form interference signal, so as to reality
Existing Terahertz Near-Field Radar Imaging, and resolution ratio is higher.
In one embodiment, Terahertz Near-Field Radar Imaging device further include:
Example platform, for placing sample；
Controller is connect with the example platform, mobile to drive sample mobile for controlling example platform, so that signal
Light emitting to sample different location.
Controller can control example platform movement, and obtain and record the coordinate of the position after being moved to a position
Information, and the coordinate information is sent to processor.
In one embodiment, data processing unit uses driving of the labview software realization to controller, current to obtain
The coordinate information of the corresponding Sample Scan point of received electric signal.Image restoring unit sends out controller by matlab program pin
The corresponding electric signal sent of the coordinate information and detector of each scanning element sent and progress data processing, to restore sample drawing
Picture is simultaneously shown.
Sample can be fixed in the tip end distance of near field of probe unit via electronic control translation stage, by sweeping point by point
It retouches, the corresponding electric signal of Terahertz interference signal of available each scanning element of sample surfaces of detector, via processing mould
Block is handled, and can obtain the sample in the super-resolution imaging of terahertz wave band.
It should be understood that although each step in the flow chart of Fig. 2 is successively shown according to the instruction of arrow, this
A little steps are not that the inevitable sequence according to arrow instruction successively executes.Unless expressly state otherwise herein, these steps
It executes there is no the limitation of stringent sequence, these steps can execute in other order.Moreover, at least part in Fig. 2
Step may include that perhaps these sub-steps of multiple stages or stage are executed in synchronization to multiple sub-steps
It completes, but can execute at different times, the execution sequence in these sub-steps or stage, which is also not necessarily, successively to be carried out,
But it can be executed in turn or alternately at least part of the sub-step or stage of other steps or other steps.
The realization of the modules in Terahertz Near-Field Radar Imaging device provided in the embodiment of the present application can be computer journey
The form of sequence.The computer program can be run in terminal or server.The program module that the computer program is constituted can store
On the memory of terminal or server.When the computer program is executed by processor, realize described in the embodiment of the present application
The step of method.
Each technical characteristic of embodiment described above can be combined arbitrarily, for simplicity of description, not to above-mentioned reality
It applies all possible combination of each technical characteristic in example to be all described, as long as however, the combination of these technical characteristics is not deposited
In contradiction, all should be considered as described in this specification.
The several embodiments of the application above described embodiment only expresses, the description thereof is more specific and detailed, but simultaneously
The limitation to claim therefore cannot be interpreted as.It should be pointed out that coming for those of ordinary skill in the art
It says, without departing from the concept of this application, various modifications and improvements can be made, these belong to the protection of the application
Range.Therefore, the scope of protection shall be subject to the appended claims for the application patent.
Claims (10)
1. a kind of Terahertz Near-Field Radar Imaging device characterized by comprising
Terahertz light source module, for emitting thz laser；
Beam splitter is arranged on the optical axis of thz laser transmission, for by the thz laser be divided into signal light and
Reference light；
Reflecting module, including probe unit and reflector element, the probe unit are arranged on the optical axis of the signal optical transport,
For receiving the signal light and by the signal light emitting to sample, to excite the sample feedback to carry the anti-of sample message
Penetrate light；The reflector element is arranged on the optical axis with reference to optical transport, for receiving and reflecting the reference light；
The beam splitter is also used to receive the reflected light and the reference light, to form the reflected light and the reference light
Terahertz interference light signal；
Processing module is handled for receiving the Terahertz interference light signal, and to the Terahertz interference light signal, with
Obtain the image information of the sample.
2. Terahertz Near-Field Radar Imaging device according to claim 1, which is characterized in that the processing module includes:
Detector is converted to for receiving and detecting the Terahertz interference light signal, and by the Terahertz interference light signal
Electric signal；
Processor carries out digitized processing for receiving the electric signal, and to the electric signal, to obtain the figure of the sample
As information.
3. Terahertz Near-Field Radar Imaging device according to claim 1, which is characterized in that the needle point of the probe unit is gold
Belong to needle point, and the radius of the metal needle point is 10-50 nanometers.
4. Terahertz Near-Field Radar Imaging device according to claim 3, which is characterized in that the metal needle point and the sample
Distance be nanometer scale.
5. Terahertz Near-Field Radar Imaging device according to claim 1, which is characterized in that described device further includes multiple reflections
Mirror is arranged on the optical axis of the signal optical transport, and for changing the outgoing route of the signal light, the signal light is sent out
It is incident upon the probe unit.
6. Terahertz Near-Field Radar Imaging device according to claim 2, which is characterized in that described device further includes that collimation is saturating
Mirror is arranged between the detector and the beam splitter, for carrying out collimation processing to the Terahertz interference light signal.
7. Terahertz Near-Field Radar Imaging device according to claim 1, which is characterized in that described device further include:
Example platform, for placing the sample；
The processing module is also connect with the example platform, mobile to drive the sample to move for controlling the example platform
It is dynamic, so that different location of the signal light emitting to the sample.
8. Terahertz Near-Field Radar Imaging device according to claim 2, which is characterized in that the detector is two pole of Schottky
Pipe.
9. Terahertz Near-Field Radar Imaging device according to claim 1, which is characterized in that the terahertz light source module is too
Hertz gas laser or Terahertz quantum cascaded laser.
10. a kind of Terahertz Near-Field Radar Imaging method is based on Terahertz Near-Field Radar Imaging device, the Terahertz Near-Field Radar Imaging device packet
It includes: terahertz light source module, beam splitter, reflecting module and processing module；It is characterized in that, which comprises
It controls terahertz light source module and emits thz laser；
The thz laser is divided into signal light and reference light；
Control reflecting module receives the signal light and by the signal light emitting to sample, to excite the sample feedback to carry
The reflected light of sample message；It receives and reflects the reference light；
The reflected light and the reference light are received, to form the Terahertz interference light letter of the reflected light and the reference light
Number；
It controls processing module and receives the Terahertz interference light signal, and the Terahertz interference light signal is handled, with
Obtain the image information of the sample.
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| CN201811612958.0A CN109696422A (en) | 2018-12-27 | 2018-12-27 | Terahertz Near-Field Radar Imaging device and method |
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