CN113218910A - Terahertz imaging system and method based on super-surface structure - Google Patents
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Abstract
The invention discloses a terahertz imaging system and method based on a super-surface structure, which comprises the following steps: the terahertz detector is characterized by also comprising a spatial modulation super-surface module; the terahertz source generates terahertz waves, the terahertz waves penetrate through the imaging target and then reach the spatial modulation super-surface module, and the spatial modulation super-surface module performs spatial modulation on the terahertz waves; the terahertz wave after being spatially modulated is received by a terahertz detector, the terahertz detector sends the received signal to an image restoration module, and the image restoration module realizes image restoration of an imaging target by using a compressed sensing and signal restoration algorithm; the spatial modulation super-surface module with the two-dimensional plane structure is mature in processing technology, easy to process, simple in modulation mode and convenient to regulate and control; and because the compressed sensing principle is used, the data acquisition times are lower, the imaging speed is higher, and the data storage capacity is lower.
Description
Technical Field
The invention relates to the technical field of imaging, in particular to a terahertz imaging system and method based on a super-surface structure.
Background
At present, imaging in the terahertz (0.1-10 THz) band is receiving more and more attention, and the main reason is that terahertz waves have unique ability of transmitting a large amount of optical opaque medium materials, such as plastics, semiconductors and the like. Compared with X-rays, terahertz waves have low energy properties, i.e., do not damage the human body and the object to be measured under the irradiation of terahertz waves. Due to the unique properties of terahertz waves, terahertz imaging technology has wide prospects in the aspects of security inspection, biomedicine, industry and the like.
The existing terahertz imaging system generally adopts focal plane array type terahertz detection imaging or point-by-point mechanical scanning imaging, wherein the focal plane array terahertz detector has high requirements on the manufacturing process, high cost and weak anti-interference capability; the point-by-point mechanical scanning imaging only needs a single-pixel detector, the imaging target is scanned and imaged in a sampling mechanical movement mode, and the method has the advantages of low cost, simple structure, strong anti-interference capability and the like, but each pixel of the image can obtain the final image only by scanning in a complete time, so that the acquisition time and the data storage amount are greatly increased.
Disclosure of Invention
The invention provides a terahertz imaging system and method based on a super-surface structure, and solves the problems of low imaging speed and large data storage amount of the conventional terahertz imaging system by combining a terahertz time-domain spectroscopy system and a terahertz super-surface structure.
The invention is realized by the following technical scheme:
a terahertz imaging system based on a super-surface structure, comprising: the terahertz detector comprises a terahertz source, a terahertz detector and an image restoration module, and further comprises a spatial modulation super-surface module;
the terahertz source generates terahertz waves, the terahertz waves penetrate through the imaging target and then reach the spatial modulation super-surface module, and the spatial modulation super-surface module performs spatial modulation on the terahertz waves;
the terahertz wave after being spatially modulated is received by the terahertz detector, the terahertz detector sends the received signal to the image restoration module, and the image restoration module realizes image restoration of the imaging target by using a compressed sensing and signal restoration algorithm.
The working principle of the scheme is as follows: the terahertz source in the terahertz time-domain spectroscopy system generates terahertz waves, the radiated terahertz waves penetrate through an imaging object, the terahertz waves are spatially modulated through the spatial modulation super-surface module, the spatially modulated terahertz waves are received by the terahertz detector, signals received by the terahertz detector are collected through the data acquisition unit and then transmitted to the image restoration module, and the image reconstruction is realized by combining a compression sensing and signal restoration algorithm, so that the terahertz image of the imaging object can be obtained. Compared with the traditional focal plane array terahertz detection imaging system, the spatial modulation super-surface module used in the scheme is a two-dimensional plane structure, and the processing technology is mature and easy to process; and due to the use of a compressed sensing principle, compared with the traditional point-by-point mechanical scanning imaging, the imaging system has the advantages of lower data acquisition times, higher imaging speed and lower data storage capacity.
The further optimization scheme is that the method further comprises the following steps: the terahertz detector comprises a first terahertz lens, a second terahertz lens and a third terahertz lens, wherein the first terahertz lens is arranged between a terahertz source and an imaging target, the second terahertz lens is arranged between the imaging target and a spatial modulation super-surface module, and the third terahertz lens is arranged between the spatial modulation super-surface module and a terahertz detector.
The further optimization scheme is that the spatial modulation super-surface module comprises a super-surface control module and an HEMT terahertz super-surface structure, the HEMT terahertz super-surface structure is an array formed by a plurality of HEMT opening modulation units, and the super-surface control module realizes spatial modulation of terahertz waves by changing the voltage of each HEMT opening modulation unit.
The HEMT terahertz super-surface structure used for spatially modulating the terahertz waves can be designed into a 16 x 16 or 32 x 32 super-surface array according to the actual imaging requirement, and any unit in the HEMT terahertz super-surface structure can be independently controlled through the super-surface control module, so that the modulation of the terahertz waves is realized.
The HEMT opening modulation unit comprises a semiconductor substrate and an epitaxial layer positioned on the surface of the semiconductor substrate, wherein an ohmic electrode, a Schottky electrode, a power supply and a modulation array are arranged on the epitaxial layer; the modulation array is formed by M multiplied by N modulation array elements in periodic arrangement, wherein M is the number of the longitudinal arrangement periods of the modulation array elements, and N is the number of the transverse arrangement periods of the modulation array elements;
each modulation array element is composed of two metal rods with different lengths, the two metal rods are collinear and are reserved with openings, the unopened ends of the metal rods are vertically connected with a grid feeder line, and the grid feeder line is vertically connected with a Schottky electrode; the opening end of the metal rod is vertically connected with a source-drain feeder through the HEMT structure, and the source-drain feeder is vertically connected to the ohmic electrode; the Schottky electrode is connected with the negative electrode of the power supply, and the ohmic electrode is connected with the positive electrode of the power supply.
The basic modulation array element of the super-surface structure is integrally of an I-shaped structure with an opening, the structure is easy to process, and the parasitic effect is small. When voltage is applied to the modulation array element, resonance is generated at 90GHz, and the transmission coefficient of the resonance is 0.014; when a voltage is applied, the structure generates resonance at 220GHz and 263GHz, and the transmission coefficients of the resonance are 0.04 and 0.214 respectively. The modulation depths at 90GHz, 220GHz, and 263GHz were calculated to be 99%, 96%, and 61%, respectively. Modulation of terahertz waves can thus be achieved by varying the voltage.
The further optimization scheme is that,
the semiconductor substrate is made of silicon carbide and has the thickness of 475 microns;
the epitaxial layer is made of gallium nitride;
the HEMT structure is made of AlGaN or GaN;
the ohmic electrode is made of Ni;
the Schottky electrode is made of Ti;
the grid feeder line is made of Au, the width of the grid feeder line is 2 micrometers, and the thickness of the grid feeder line is 0.2 micrometer;
the source and drain feeder is made of Au, the width of the Au is 10 mu m, and the thickness of the Au is 0.2 mu m;
the further optimization scheme is that the thickness of the metal rod is 0.2 mu m, the width of the metal rod is 10 mu m, the length of the longer metal rod is 146 mu m, and the length of the shorter metal rod is 108 mu m.
The HEMT terahertz super-surface structure used combines a High Electron Mobility Transistor (HEMT) with high-speed dynamic characteristics, and the basic working principle is as follows: because the HEMT structure is designed at the opening of the super-surface structure, when bias voltage is not applied, the metal rod opening of the super-surface structure is short-circuited because 2DEG (two-dimensional electron gas) with high concentration exists in the HEMT channel, and at the moment, the super-surface structure can generate a resonance mode; when the applied bias voltage is gradually increased, the 2DEG in the HEMT channel is gradually depleted, when the applied bias voltage reaches a certain value, the 2DEG is completely depleted, and at the moment, the opening of the super-surface structure metal rod is opened, and another resonance mode is generated. Therefore, mode conversion of the super-surface structure is achieved by changing voltage, and regulation and control of terahertz waves are further achieved.
The further optimization scheme is that the terahertz wave image restoration device further comprises a data acquisition module, wherein the data acquisition module acquires terahertz wave signals received by the terahertz wave detector and performs data preprocessing to obtain a signal intensity matrix y and sends the signal intensity matrix y to the image restoration module;
the data preprocessing process comprises the following steps:
firstly, converting terahertz signals into electric signals;
the electrical signal is amplified by an SR570 preamplifier;
and the amplified electric signals are collected by an SR830 phase-locked amplifier to form a signal intensity matrix y.
The further optimization scheme is that the mathematical model of compressed sensing is as follows: y is equal to phi X,
in the formula: y is the signal intensity matrix, phi is the sensing matrix, and X is the image signal to be restored.
Sparsity or compressibility of signals is an important premise of compressed sensing, and real signals existing in nature are generally not absolutely sparse, but can be approximately sparse in a certain transform domain, namely, compressible signals. For example, the transform domain may be a discrete cosine transform, a wavelet transform, or the like. The method comprises the steps of firstly obtaining a signal intensity matrix y by measurement for image reconstruction, then carrying out sparse representation on a certain sparse basis because a general image signal X is not sparse, namely X is phi theta which is a known sparse basis matrix, theta is a sparse vector (the matrix A phi can be obtained only if K of theta are nonzero values (K < < N), representing theta by the signal intensity matrix y and the matrix A obtained by measurement, and reconstructing an image by utilizing compressed sensing according to the known sparse basis matrix psi.
The further optimization scheme is that the signal restoration algorithm uses an orthogonal matching pursuit algorithm or a compressed sampling matching pursuit algorithm. The core idea of the orthogonal matching pursuit algorithm is that column vector orthogonalization is realized through Schmidt orthogonalization, and in the iterative process, atoms after orthogonalization are subjected to projection comparison with signals to obtain the residual errors, so that the residual errors and the previously selected atoms are always in an orthogonal relation. And then, each iteration updates the selected atom set to form a new atom set, so that the calculation efficiency of the algorithm is further improved, and repeated searching of atoms is avoided. Therefore, the orthogonal matching pursuit algorithm is an efficient compressed sensing image restoration algorithm.
Based on the terahertz imaging system, the scheme provides a terahertz imaging method based on a super-surface structure, and the method comprises the following steps:
the terahertz waves which penetrate through the imaging target are subjected to spatial modulation through a spatial modulation super-surface module;
collecting a terahertz wave signal after spatial modulation and carrying out data preprocessing;
and realizing image restoration of the imaging target by using a compressed sensing and signal restoration algorithm based on the data after data preprocessing.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. according to the terahertz imaging system and method based on the super-surface structure, the spatial modulation super-surface module with the two-dimensional plane structure is used, the processing technology is mature, and the processing is easy; and due to the use of a compressed sensing principle, compared with the traditional point-by-point mechanical scanning imaging, the imaging system has the advantages of lower data acquisition times, higher imaging speed and lower data storage capacity.
2. According to the terahertz imaging system and method based on the super-surface structure, the basic modulation array element of the super-surface structure is combined with a High Electron Mobility Transistor (HEMT) with high-speed dynamic characteristics to realize modulation of terahertz waves, the modulation mode is simple, and the regulation and control are convenient.
3. According to the terahertz imaging system and method based on the super-surface structure, the whole basic modulation array element of the super-surface structure is of an I-shaped structure with an opening, the structure is easy to process, and the parasitic effect is small.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a structural schematic diagram of a terahertz imaging system based on a super-surface structure;
FIG. 2 is a schematic diagram of a terahertz super-surface structure of a HEMT;
fig. 3 is a schematic diagram of a modulation array element structure.
Reference numbers and corresponding part names:
the device comprises a semiconductor substrate 1, an epitaxial layer 2, an ohmic electrode 3, a Schottky electrode 4, a source-drain electrode feeder 5, a grid electrode feeder 6, a HEMT structure 7, a modulation array 8 and a modulation array element 81.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that: it is not necessary to employ these specific details to practice the present invention. In other instances, well-known structures, circuits, materials, or methods have not been described in detail so as not to obscure the present invention.
Throughout the specification, reference to "one embodiment," "an embodiment," "one example," or "an example" means: the particular features, structures, or characteristics described in connection with the embodiment or example are included in at least one embodiment of the invention. Thus, the appearances of the phrases "one embodiment," "an embodiment," "one example" or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and/or sub-combination in one or more embodiments or examples. Further, those of ordinary skill in the art will appreciate that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
In the description of the present invention, it is to be understood that the terms "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "high", "low", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore, are not to be construed as limiting the scope of the present invention.
Example 1
As shown in fig. 1, the present invention provides a terahertz imaging system based on a super-surface structure, including: the terahertz detector comprises a terahertz source, a terahertz detector and an image restoration module, and further comprises a spatial modulation super-surface module;
the terahertz source generates terahertz waves, the terahertz waves penetrate through the imaging target and then reach the spatial modulation super-surface module, and the spatial modulation super-surface module performs spatial modulation on the terahertz waves;
the terahertz wave after being spatially modulated is received by the terahertz detector, the terahertz detector sends the received signal to the image restoration module, and the image restoration module realizes image restoration of the imaging target by using a compressed sensing and signal restoration algorithm.
Further comprising: the terahertz detector comprises a first terahertz lens, a second terahertz lens and a third terahertz lens, wherein the first terahertz lens is arranged between a terahertz source and an imaging target, the second terahertz lens is arranged between the imaging target and a spatial modulation super-surface module, and the third terahertz lens is arranged between the spatial modulation super-surface module and a terahertz detector.
The spatial modulation super-surface module comprises a super-surface control module and a HEMT terahertz super-surface structure, wherein the HEMT terahertz super-surface structure is an array formed by a plurality of HEMT opening modulation units, and the super-surface control module realizes the spatial modulation of terahertz waves by changing the voltage of each HEMT opening modulation unit.
As shown in fig. 2 and fig. 3, the HEMT open modulation unit includes a semiconductor substrate 1 and an epitaxial layer 2 located on the surface of the semiconductor substrate, wherein an ohmic electrode 3, a schottky electrode 4, a power supply and a modulation array 8 are arranged on the epitaxial layer 3; the modulation array 8 is formed by M multiplied by N modulation array elements 81 in periodic arrangement, wherein M is the number of the longitudinal arrangement periods of the modulation array elements 81, and N is the number of the transverse arrangement periods of the modulation array elements 81;
each modulation array element 81 is composed of two metal rods with different lengths, the two metal rods are collinear and are provided with openings, the unopened ends of the metal rods are vertically connected with a grid feeder line 6, and the grid feeder line 6 is vertically connected with a Schottky electrode 4; the opening end of the metal rod is vertically connected with the source-drain feeder 5 through the HEMT structure 7, and the source-drain feeder 5 is vertically connected to the ohmic electrode 3; the Schottky electrode 4 is connected with the negative electrode of the power supply, and the ohmic electrode 3 is connected with the positive electrode of the power supply.
The material of the semiconductor substrate 1 is silicon carbide, and the thickness is 475 micrometers; the epitaxial layer 2 is made of gallium nitride; the HEMT structure 7 is made of AlGaN or GaN; the material of the ohmic electrode 3 is Ni; the material of the Schottky electrode 4 is Ti; the grid feeder line 6 is made of Au, the width is 2 μm, and the thickness is 0.2 μm; the source and drain feeder 5 is made of Au, the width is 10 μm, and the thickness is 0.2 μm; the thickness of the metal rod is 0.2 μm, the width is 10 μm, the length of the longer metal rod is 146 μm, and the length of the shorter metal rod is 108 μm.
The terahertz wave signal processing device further comprises a data acquisition module, wherein the data acquisition module acquires a terahertz wave signal received by the terahertz wave detector and performs data preprocessing to obtain a signal intensity matrix y and sends the signal intensity matrix y to the image restoration module;
the data preprocessing process comprises the following steps: firstly, converting terahertz signals into electric signals; the electrical signal is amplified by an SR570 preamplifier; and the amplified electric signals are collected by an SR830 phase-locked amplifier to form a signal intensity matrix y.
The mathematical model of compressed sensing is: y is equal to phi X,
in the formula: y is the signal intensity matrix, phi is the sensing matrix, and X is the image signal to be restored.
The signal restoration algorithm uses an orthogonal matching pursuit algorithm or a compressed sampling matching pursuit algorithm.
Example 2
Based on the previous embodiment. The embodiment provides a terahertz imaging method based on a super-surface structure, which comprises the following steps:
the terahertz waves which penetrate through the imaging target are subjected to spatial modulation through a spatial modulation super-surface module;
collecting a terahertz wave signal after spatial modulation and carrying out data preprocessing;
and realizing image restoration of the imaging target by using a compressed sensing and signal restoration algorithm based on the data after data preprocessing.
In the imaging process, firstly, the terahertz waves are collimated and focused by a lens to irradiate an imaging target, and then, according to a sensing matrix phi, a super-surface control module is used for controlling whether voltage is applied to each pixel unit of the HEMT opening modulation unit, such as: 0 denotes that no voltage is applied to the pixel unit (HEMT aperture modulation unit), and 1 denotes that a voltage is applied to the pixel unit (HEMT aperture modulation unit), so that modulation of terahertz waves containing imaging target two-dimensional image information can be achieved. If the size of the imaging image is 32 × 32 and the compression ratio is 0.5, the super-surface structure needs to be controlled repeatedly and data acquisition needs to be carried out 512 times, and then the acquired data is subjected to image restoration through a restoration algorithm in a computer, so that a two-dimensional terahertz image is obtained.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A terahertz imaging system based on a super-surface structure, comprising: the terahertz detector is characterized by also comprising a spatial modulation super-surface module;
the terahertz source generates terahertz waves, the terahertz waves penetrate through the imaging target and then reach the spatial modulation super-surface module, and the spatial modulation super-surface module performs spatial modulation on the terahertz waves;
the terahertz wave after being spatially modulated is received by the terahertz detector, the terahertz detector sends the received signal to the image restoration module, and the image restoration module realizes image restoration of the imaging target by using a compressed sensing and signal restoration algorithm.
2. The terahertz imaging system based on the super-surface structure, according to claim 1, further comprising: the terahertz detector comprises a first terahertz lens, a second terahertz lens and a third terahertz lens, wherein the first terahertz lens is arranged between a terahertz source and an imaging target, the second terahertz lens is arranged between the imaging target and a spatial modulation super-surface module, and the third terahertz lens is arranged between the spatial modulation super-surface module and a terahertz detector.
3. The terahertz imaging system based on the super-surface structure, according to claim 1, wherein the spatially modulated super-surface module comprises a super-surface control module and a HEMT terahertz super-surface structure, the HEMT terahertz super-surface structure is an array formed by a plurality of HEMT opening modulation units, and the super-surface control module realizes spatial modulation of terahertz waves by changing the voltage of each HEMT opening modulation unit.
4. The terahertz imaging system based on the super-surface structure is characterized in that the HEMT opening modulation unit comprises a semiconductor substrate (1) and an epitaxial layer (2) positioned on the surface of the semiconductor substrate, wherein an ohmic electrode (3), a Schottky electrode (4), a power supply and a modulation array (8) are arranged on the epitaxial layer (2); the modulation array (8) is formed by M multiplied by N modulation array elements (81) in periodic arrangement, wherein M is the number of the longitudinal arrangement periods of the modulation array elements (81), and N is the number of the transverse arrangement periods of the modulation array elements (81);
each modulation array element (81) is composed of two metal rods with different lengths, the two metal rods are collinear and are provided with openings, the unopened ends of the metal rods are vertically connected with a grid feeder line (6), and the grid feeder line 6 is vertically connected with a Schottky electrode (4); the opening end of the metal rod is vertically connected with the source-drain feeder (5) through the HEMT structure (7), and the source-drain feeder (5) is vertically connected to the ohmic electrode (3); the Schottky electrode (4) is connected with the negative electrode of the power supply, and the ohmic electrode (3) is connected with the positive electrode of the power supply.
5. The terahertz imaging system based on the super-surface structure is characterized in that,
the semiconductor substrate (1) is made of silicon carbide and has the thickness of 475 microns;
the epitaxial layer (2) is made of gallium nitride;
the HEMT structure (7) is made of AlGaN or GaN;
the ohmic electrode (3) is made of Ni;
the Schottky electrode (4) is made of Ti;
the grid feeder line (6) is made of Au, the width of the grid feeder line is 2 micrometers, and the thickness of the grid feeder line is 0.2 micrometers;
the source and drain feeder (5) is made of Au, the width of the Au is 10 mu m, and the thickness of the Au is 0.2 mu m.
6. The terahertz imaging system based on the super-surface structure, according to claim 4, wherein the metal rod has a thickness of 0.2 μm and a width of 10 μm, the longer metal rod has a length of 146 μm, and the shorter metal rod has a length of 108 μm.
7. The terahertz imaging system based on the super-surface structure as claimed in claim 1, further comprising a data acquisition module, wherein the data acquisition module acquires the terahertz wave signal received by the terahertz detector and performs data preprocessing to obtain a signal intensity matrix y, and sends the signal intensity matrix y to the image restoration module;
the data preprocessing process comprises the following steps:
firstly, converting terahertz signals into electric signals;
the electrical signal is amplified by an SR570 preamplifier;
and the amplified electric signals are collected by an SR830 phase-locked amplifier to form a signal intensity matrix y.
8. The terahertz imaging system based on the super-surface structure, according to claim 7, wherein the mathematical model of compressive sensing is as follows: y is equal to phi X,
in the formula: y is the signal intensity matrix, phi is the sensing matrix, and X is the image signal to be restored.
9. The terahertz imaging system based on the super-surface structure, according to claim 7, wherein the signal recovery algorithm uses an orthogonal matching pursuit algorithm or a compressive sampling matching pursuit algorithm.
10. A terahertz imaging method based on a super-surface structure, applied to any one of the terahertz imaging systems based on the super-surface structure of claims 1-9, comprising:
the terahertz waves which penetrate through the imaging target are subjected to spatial modulation through a spatial modulation super-surface module;
collecting a terahertz wave signal after spatial modulation and carrying out data preprocessing;
and realizing image restoration of the imaging target by using a compressed sensing and signal restoration algorithm based on the data after data preprocessing.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116385296A (en) * | 2023-04-04 | 2023-07-04 | 西安电子科技大学 | Terahertz imaging method based on adaptive soft threshold shrinkage |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103346406A (en) * | 2013-05-20 | 2013-10-09 | 电子科技大学 | Terahertz wave spatial external modulator based on high electron mobility transistor |
| CN105158196A (en) * | 2015-05-12 | 2015-12-16 | 上海理工大学 | Terahertz wave 3D image acquisition method and system |
| CN105549228A (en) * | 2015-12-21 | 2016-05-04 | 电子科技大学 | Terahertz space phase modulator based on high electron mobility transistor |
| US20170236912A1 (en) * | 2017-05-04 | 2017-08-17 | University Of Electronic Science And Technology Of China | Spatial terahertz wave phase modulator based on high electron mobility transistor |
| CN107144985A (en) * | 2017-06-21 | 2017-09-08 | 电子科技大学 | A kind of netted automatically controlled terahertz wave modulator of HEMT arrays being dislocatedly distributed |
| CN109004060A (en) * | 2017-06-26 | 2018-12-14 | 苏州科技大学 | Terahertz wave detector |
| CN109297925A (en) * | 2018-10-09 | 2019-02-01 | 天津大学 | A kind of Terahertz high-resolution fast imaging device based on splits' positions perception |
| JP2019033464A (en) * | 2017-08-10 | 2019-02-28 | 国立大学法人大阪大学 | Terahertz unit for generating terahertz waves |
| CN109490241A (en) * | 2018-12-07 | 2019-03-19 | 江南大学 | Quick dynamic Terahertz near field imaging system and its construction method based on photoconductive antenna array |
| US20200249503A1 (en) * | 2019-07-31 | 2020-08-06 | University of Electronics Science and Technology of China | Wideband terahertz modulator based on gradual openings |
| CN111579521A (en) * | 2020-05-06 | 2020-08-25 | 中国科学院沈阳自动化研究所 | Terahertz compression imaging optimization method and system based on data selection |
| CN111854945A (en) * | 2020-07-31 | 2020-10-30 | 重庆邮电大学 | Single-pixel ultraviolet polarization imaging method and system |
| CN111884593A (en) * | 2020-08-04 | 2020-11-03 | 重庆邮电大学 | Ring-shaped opening terahertz amplitude modulator based on HEMT and manufacturing method |
-
2021
- 2021-05-13 CN CN202110521359.3A patent/CN113218910B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103346406A (en) * | 2013-05-20 | 2013-10-09 | 电子科技大学 | Terahertz wave spatial external modulator based on high electron mobility transistor |
| CN105158196A (en) * | 2015-05-12 | 2015-12-16 | 上海理工大学 | Terahertz wave 3D image acquisition method and system |
| CN105549228A (en) * | 2015-12-21 | 2016-05-04 | 电子科技大学 | Terahertz space phase modulator based on high electron mobility transistor |
| US20170236912A1 (en) * | 2017-05-04 | 2017-08-17 | University Of Electronic Science And Technology Of China | Spatial terahertz wave phase modulator based on high electron mobility transistor |
| CN107144985A (en) * | 2017-06-21 | 2017-09-08 | 电子科技大学 | A kind of netted automatically controlled terahertz wave modulator of HEMT arrays being dislocatedly distributed |
| CN109004060A (en) * | 2017-06-26 | 2018-12-14 | 苏州科技大学 | Terahertz wave detector |
| JP2019033464A (en) * | 2017-08-10 | 2019-02-28 | 国立大学法人大阪大学 | Terahertz unit for generating terahertz waves |
| CN109297925A (en) * | 2018-10-09 | 2019-02-01 | 天津大学 | A kind of Terahertz high-resolution fast imaging device based on splits' positions perception |
| CN109490241A (en) * | 2018-12-07 | 2019-03-19 | 江南大学 | Quick dynamic Terahertz near field imaging system and its construction method based on photoconductive antenna array |
| US20200249503A1 (en) * | 2019-07-31 | 2020-08-06 | University of Electronics Science and Technology of China | Wideband terahertz modulator based on gradual openings |
| CN111579521A (en) * | 2020-05-06 | 2020-08-25 | 中国科学院沈阳自动化研究所 | Terahertz compression imaging optimization method and system based on data selection |
| CN111854945A (en) * | 2020-07-31 | 2020-10-30 | 重庆邮电大学 | Single-pixel ultraviolet polarization imaging method and system |
| CN111884593A (en) * | 2020-08-04 | 2020-11-03 | 重庆邮电大学 | Ring-shaped opening terahertz amplitude modulator based on HEMT and manufacturing method |
Non-Patent Citations (2)
| Title |
|---|
| HOSOTANI TOMOTAKA等: "Terahertz emission in an InGaAs-based dual-grating-gate high-electron-mobility transistor plasmonic photomixer" * |
| 杨朝晖 等: "基于二氧化钒复合超表面的太赫兹带宽可调极化转换器" * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116385296A (en) * | 2023-04-04 | 2023-07-04 | 西安电子科技大学 | Terahertz imaging method based on adaptive soft threshold shrinkage |
| CN116385296B (en) * | 2023-04-04 | 2024-02-27 | 西安电子科技大学 | Terahertz imaging method based on adaptive soft threshold shrinkage |
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