Beijing Key Laboratory for Terahertz Spectroscopy and Imaging

Laboratory for, China

Beijing Key Laboratory for Terahertz Spectroscopy and Imaging

Laboratory for, China

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Zhang C.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Zhang C.,Capital Normal University | Su B.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Su B.,Capital Normal University | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

Waveguides, which can transmit high frequency electromagnetic waves, have a lot of types, such as microstrip line (MSL), coplanar waveguides (CPW), coplanar-strip-line (CPS) and so forth. In the waveguides mentioned above, CPW has the advantages of easy fabrication and superior performance. Meanwhile MSL also has many advantages such as small size, light weight and high spectral resolution, but it also shows a higher attenuation and dispersion compared with the free-space waveguides. So in on-chip terahertz system, CPW and MSL was used as waveguides to transmit terahertz waves and the HFSS software was used to simulate and analyze the transmission characteristics of the MSL and CPW based on the on-chip system researched by University of Leeds (America) and Hiroshima University (Japan). The simulation results show that the scattering parameters of the two waveguides are similar to the known literatures. Meanwhile we also have designed a new structure of MSL which is applicable for our on-chip system. © 2016 SPIE.


Zang J.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Xie Z.,Harbin Institute of Technology | Zhang Y.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Zhang Y.,Harbin Institute of Technology
Optics Letters | Year: 2013

A simple optical image encryption system with spatially incoherent illumination is proposed. Only one Fourier lens and one random phase plate are contained in this system. The original image is perturbed by a random phase-only mask located on the aperture plane. The encrypted information is the only intensity distribution that can be directly recorded by a CCD or CMOS. The decryption procedure can be performed digitally and the random phase distribution works as the decryption key. Numerical simulations and experimental results demonstrate the validity of the proposed method. © 2013 Optical Society of America.


Su B.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Su B.,Capital Normal University | Duan G.,Beijing Institute of Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

Non-touch measurement is an important technology in many domains such as the monitoring of tool breakage and tool wear, et al. Based on the method of curve fitting and demanding inflection point, we present a high accuracy non-touch diameter measurement system. The measurement system comprise linear array CCD, CCD driving circuit, power supply, workseat, light source, data acquisition card and so on. The picture element of the linear array CCD is 2048, and the size of every pixel and the spacing of adjacent pixels have the same size of 14μm×14μm. The stabilized voltage supply has a constant voltage output of 3V. The light is generated by a halogen tungsten lamp, which does not represent any risk to the health of the whole system. The data acquisition card converts the analog signal to digital signal with the accuracy of 12 bit. The error of non-uniform of the CCD pixels in sensitivity and the electrical noise error are indicated in detail. The measurement system has a simple structure, high measuring precision, and can be carried out automatically. Experiment proves that the diameter measurement of the system is within the range of Φ0.5∼Φ10mm, and the total measuring unstability of the system is within the range of ± 1.4μm. © 2011 SPIE.


Su B.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Su B.,Capital Normal University | Duan G.,Beijing Institute of Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

We have developed a novel THz detector which uses the cantilever technology and surface plasmon resonance (SPR) technology to achieve a high sensitivity. The Micro Electro Mechanical System (MEMS) technology is adopted to fabricate the detector, which comprise thermo-sensitive bi-material micro-cantilever, prism and optical readout system. The bi-material of Si 3N 4 and Al is used to fabricate the micro-cantilever because of the good absorption characteristic for THz of Si 3N 4 and the great difference in thermal expansion coefficient of the bi-material for the deformation of the micro-cantilever. In order to increase the deformation of micro-cantilever, the method of computer simulation is used to obtain the optimal structure of micro-cantilever and the thickness of Si 3N 4 and Al. The function of the glass prism is to make the incident light generate total reflection under certain conditions. The gold film is sputtering on the top of glass slide using the method of magnetron sputtering and it is necessary for the generation of SPR performance. The optical readout system can make the change of cantilever bending convert to the change of reflection luminous intensity proportionally. The heat on the micro-cantilever coming from the THz radiation can lose easily in the air, so the detector is placed vertically in a cylindrical vacuum chamber which is sealed with quartz glasses and polyethylene lamina at the two end surfaces respectively. The quartz glass is used for the incidence of visible polarized light and the polyethylene lamina for the THz radiation. In order to maintain the vacuum performance of the chamber, the mechanical pump and molecular pump are adopted. In static mode, THz radiation absorption raises the temperature of micro-cantilever, so it bends proportionally. The micro-cantilever bending changes the thicknesses of the gap between the micro-cantilever and the metallic thin film on the micro-prism. It will result in a shift of the SPR angle. Therefore, the surface plasmon excitation efficiency and therewith the measured at a fixed incident angle reflectance of a metallic film will be changed almost proportionally to the cantilever bending. Consequently, the radiation energy of THz can be determined via the metallic film reflectivity change. Finally, the technology of image processing is introduced in detail. © 2011 SPIE.


Zhu Q.,Beijing University of Technology | Zhu Q.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Wang D.,Beijing University of Technology | Ye J.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Zhang Y.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging
Optics Communications | Year: 2010

Employing the surface plasmon polaritons (SPPs), a kind of coupled metallic squareness ring waveguide structure is presented. Its properties has been analyzed with the finite different time domain method and the coupling length has been derived from the coupled mode theory. It is demonstrated that the SPPs excited by the light with different wavelength will come out from different output port due to different coupling length. By appropriately designing the structure, it can be utilized to realize some optics devices such as multiple-wavelength sorter and beam splitter. This will break through the diffraction limit of traditional optical devices. © 2009 Elsevier B.V. All rights reserved.


Song L.-L.,Capital Normal University | Jin Q.-H.,Capital Normal University | Cui L.-N.,Capital Normal University | Zhang C.-L.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging
Inorganica Chimica Acta | Year: 2010

At ambient temperature, two silver(I) complexes [Ag 4(SO 4) 2(dppm) 4]·5CH 3CH 2OH·1/2H 2O (1) and [Ag 2(SO 4)(dppm) 2(2-ampz)]·CH 3OH·H 2O (2) (dppm = bis(diphenylphosphino)methane, 2-ampz = 2-aminopyrazine) were obtained by the reaction of Ag 2SO 4 with dppm in the presence of pyrazine or 2-aminopyrazine. They are characterized by IR, X-ray crystallography, luminescence and 1H, 31P NMR spectroscopy. Complex 1 is a tetranuclear cluster. In complex 2, the units [Ag 2(SO 4)(dppm) 2] are connected by 2-aminopyrazine to form a 1D linear polymer. Due to the subtle interactions of different nitrogen heterocyclic ligands with silver ions, two SO 4 2- anions in 1 adopt μ 3-O, O′, O′ and unique μ 4-O, O, O′, O′ bonding modes respectively, while SO 4 2- anion in 2 adopts μ-O, O′ bonding mode. © 2010 Elsevier B.V. All rights reserved.


Liu C.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Ye J.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Zhang Y.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging
Optics Communications | Year: 2010

By using the finite-difference time domain method, the transmission properties of terahertz wave passing through two different periodic subwavelength structures on InSb semiconductor slabs under different temperatures have been investigated. The results show that the peak transmittance increases and the transmittance peak has a blue shift when the temperature is increasing. It is extremely versatile to control the tunable THz filter by varying the temperature. © 2009 Elsevier B.V. All rights reserved.


Jin Q.-H.,Capital Normal University | Hu K.-Y.,Capital Normal University | Song L.-L.,Capital Normal University | Wang R.,Capital Normal University | And 3 more authors.
Polyhedron | Year: 2010

Five new copper(I)/silver(I) complexes containing 2-aminopyridine, [Cu(μ-Cl)(2-Apy)(PPh3)]2(1), [Ag(μ-Cl)(2-Apy)(PPh3)]2(2), [Ag(μ-Br)(2-Apy)PPh3)]2(3), [Ag(μ-ONO2)(2-Apy)(PPh3)]2(4), [Ag(μ-ONO2)(2-Apy)(AsPh3)]2(5) have been synthesised for the first time. Complexes 1-5 are obtained by the reactions of MX (MX = CuCl for 1; M = Ag for 2-5; X = Cl, Br for 2-3; X = NO3 for 4-5) with the monodentate ligands EPh3 (E = P for 1-4; E = As for 5) and 2-Apy in the molar ratio of 1:1:2 in the mixed solvent of CH2Cl2 and MeOH. Complexes 1-5 are characterised by IR and X-ray diffraction. In 1-5, chloride, bromide and nitrate ions bridge two metal atoms to form dinuclear complexes containing the parallelogram cores M2X2 (M = Cu, Ag). © 2009 Elsevier Ltd. All rights reserved.


Jin Q.-H.,Capital Normal University | Zhou L.-L.,Capital Normal University | Xu L.-J.,Capital Normal University | Zhang Y.-Y.,Capital Normal University | And 2 more authors.
Polyhedron | Year: 2010

Four new complexes [Cu(H2biim)2(H2O)](NO3)2 (1), [Cu(H2biim)2](ClO4)2· 2DMSO (2), [Cu(H2biim)2] [I0.36·(NO3)0.64]2 (3) and {[Cu(H2biim)2(H2O)](SiF6)} ·H2O (4) (H2biim = 2,2′-biimdazole, DMSO = dimethyl sulfoxide) have been synthesized and characterized by X-ray diffraction. The different inorganic anions NO3 -, ClO4 -, [I0.36·(NO3)0.64]- and SiF6 2 - in these complexes lead to different 3D structures. Among them, complex 3 has an interesting 3D porous structure with two [I0.36·(NO3)0.64]- ions as guests in the cavity. Compound 4 was obtained by the reaction of Cu(BF4)2 with H2biim in water in glass bottle. The robust hydrogen bond of typeV R2 1(7) played a key role in the formation of SiF6 2 - in complex 4. © 2009 Elsevier Ltd. All rights reserved.


Sun W.,Capital Normal University | Sun W.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | Wang X.,Capital Normal University | Wang X.,Beijing Key Laboratory for Terahertz Spectroscopy and Imaging | And 2 more authors.
Optik | Year: 2013

We demonstrated a continuous wave terahertz (THz) phase imaging system which can present the depth information of an object's surface interior accurately and non-invasively. With the three-step phase-shifting method, the phase images of samples which can provide the relative optical depth profile of the sample's surface and interior have been achieved. Two samples with different thickness and materials were measured to demonstrate the phase imaging ability of the system. The results show that this method is effective and the measured values agree well with the actual ones. The longitudinal resolution of the system was also measured. To exhibit the advantages of the three-step phase shifting method, the multi-wavelength imaging method was also employed and the results are compared. © 2013 Elsevier GmbH.

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