Spectroscopic measurements and terahertz imaging of the cornea are carried out by using a rapid scanning terahertz time domain spectroscopy（THz-TDS） system.A voice coil motor stage based optical delay line（VCM-ODL...Spectroscopic measurements and terahertz imaging of the cornea are carried out by using a rapid scanning terahertz time domain spectroscopy（THz-TDS） system.A voice coil motor stage based optical delay line（VCM-ODL） is developed to provide a rather simple and robust structure with both the high scanning speed and the large delay length.The developed system is used for THz spectroscopic measurements and imaging of the corneal tissue with different amounts of water content,and the measurement results show the consistence with the reported results,in which the measurement time using VCM-ODL is a factor of 360 shorter than the traditional motorized optical delay line（MDL）.With reducing the water content a monotonic decrease of the complex permittivity of the cornea is observed.The two-term Debye relaxation model is employed to explain our experimental results,revealing that the fast relaxation time of a dehydrated cornea is much larger than that of a hydrated cornea and its dielectric behavior can be affected by the presence of the biological macromolecules.These results demonstrate that our THz spectrometer may be a promising candidate for tissue hydration sensing and practical application of THz technology.展开更多
THz Radar Cross Section(RCS)measurement setup based on THz Time Domain Spectroscopy(TDS)is built to provide large scaled targets test ability in recent years.As calibrations,the metal plates and dihedrons are used in ...THz Radar Cross Section(RCS)measurement setup based on THz Time Domain Spectroscopy(TDS)is built to provide large scaled targets test ability in recent years.As calibrations,the metal plates and dihedrons are used in our experiments.The measurements are performed in a monostatic terahertz time-domain setup.The author proposed time domain and frequency domain calibration methods for angular RCS of calibrations,comparing the measurements with the theory to verify the ability of the time domain measurement setup.展开更多
Terahertz （THz） radiation, whose frequency ranges from 0.1 THz to 10.0 THz, has rich science, but limited technology. It has long been considered the last remaining scientific gap in the electromagnetic spectrum. Fa...Terahertz （THz） radiation, whose frequency ranges from 0.1 THz to 10.0 THz, has rich science, but limited technology. It has long been considered the last remaining scientific gap in the electromagnetic spectrum. Far from being fully exploited, it offers great opportunities in science, innovation, new technology, and potential applications. THz science and technology enables fundamental research directly impact our lives, from industrial quality control,展开更多
Terahertz time-domain spectroscopy(THz-TDS)was utilized to investigate the solid-state reaction between L(+)-Tartaric acid and sodium hydrogen carbonate.Solid sodium hydrogen L(+)-tartrate monohydrate was synthesized ...Terahertz time-domain spectroscopy(THz-TDS)was utilized to investigate the solid-state reaction between L(+)-Tartaric acid and sodium hydrogen carbonate.Solid sodium hydrogen L(+)-tartrate monohydrate was synthesized efficiently by mechanical grinding,which is particularly sustainable and environmentally benign.Distinct THz absorptions were observed for pure reactants and the proposed product.The reaction process could be clearly visualized by THz spectral patterns of the reaction mixtures at different grinding time.The observed results were further confirmed by synchrotron radiation X-ray powder diffraction(SRXRPD)and Fourier transform infrared (FT-IR)spectroscopy.The study demonstrates that THz-TDS is an effective novel tool to monitor solid-state reactions in pharmaceutical industry.展开更多
We give a brief review of the developments in terahertz time-domain spectroscopy(THz-TDS) systems and microcavity components for probing samples in the University of Shanghai for Science and Technology. The broadband ...We give a brief review of the developments in terahertz time-domain spectroscopy(THz-TDS) systems and microcavity components for probing samples in the University of Shanghai for Science and Technology. The broadband terahertz(THz) radiation sources based on GaAs m-i-n diodes have been investigated by applying high electric fields. Then, the free space THz-TDS and fiber-coupled THz-TDS systems produced in our lab and their applications in drug/cancer detection are introduced in detail. To further improve the signal-to-noise ratio(SNR) and enhance sensitivity, we introduce three general micro-cavity approaches to achieve tiny-volume sample detection, summarizing our previous results about their characteristics, performance, and potential applications.展开更多
Terahertz(THz) time-domain spectroscopy(TDS) has been applied to investigate liquid's optical property in recent years.However,comprehensive discussion of how to compute liquids' complex refractive indices and...Terahertz(THz) time-domain spectroscopy(TDS) has been applied to investigate liquid's optical property in recent years.However,comprehensive discussion of how to compute liquids' complex refractive indices and absorption rates are seldom reported.So,in this work,we try to find a way to compute liquids' optical property accurately and conveniently.展开更多
In this paper,we used terahertz time-domain spectroscopy(THz-TDS)over a range of 0.3–2.5 THz to investigate the formation of solid-state cocrystals of amino acids,formed by grinding mixtures of two different kinds of...In this paper,we used terahertz time-domain spectroscopy(THz-TDS)over a range of 0.3–2.5 THz to investigate the formation of solid-state cocrystals of amino acids,formed by grinding mixtures of two different kinds of amino acids.For comparison,we prepared dual-layer samples,combined by pressing two single-component pellets together without grinding.In the ground-mixture samples,some extra absorption peaks appeared,different from the characteristic peaks of the pure components,but these peaks did not appear in the dual-layer samples.Thus,these extra absorption peaks in the THz range are unique features of cocrystals.From our results,we believe that THz-TDS is a promising technique to characterize cocrystals.展开更多
In this paper, we employed terahertz time domain spectroscopy （THz-TDS） to investigate the nitrate 0 concentration in four types of nitrate solution （sodium nitrate, aluminum nitrate, calcium nitrate and magnesium ...In this paper, we employed terahertz time domain spectroscopy （THz-TDS） to investigate the nitrate 0 concentration in four types of nitrate solution （sodium nitrate, aluminum nitrate, calcium nitrate and magnesium nitrate）. Their absorption coefficient and refractive index were calculated in 0.2-2.5THz, and a logarithmic relationship was observed between NO3 concentrations and selected optical parameters regardless of the kinds of nitrate solution. Partial least square （PLS） model was built between THz-TDS and NO3 concentration. The correlation coefficient of PLS model was calculated. The results make the quantitative analysis of NO3 concentration possible by THz-TDS and indicate the bright future in practical application.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61205101)the Shenzhen Municipal Research Foundation,China(Grant Nos.GJHZ201404171134305 and JCYJ20140417113130693)the Marie Curie Actions-International Research Staff Exchange Scheme(IRSES)(Grant No.FP7 PIRSES-2013-612267)
文摘Spectroscopic measurements and terahertz imaging of the cornea are carried out by using a rapid scanning terahertz time domain spectroscopy（THz-TDS） system.A voice coil motor stage based optical delay line（VCM-ODL） is developed to provide a rather simple and robust structure with both the high scanning speed and the large delay length.The developed system is used for THz spectroscopic measurements and imaging of the corneal tissue with different amounts of water content,and the measurement results show the consistence with the reported results,in which the measurement time using VCM-ODL is a factor of 360 shorter than the traditional motorized optical delay line（MDL）.With reducing the water content a monotonic decrease of the complex permittivity of the cornea is observed.The two-term Debye relaxation model is employed to explain our experimental results,revealing that the fast relaxation time of a dehydrated cornea is much larger than that of a hydrated cornea and its dielectric behavior can be affected by the presence of the biological macromolecules.These results demonstrate that our THz spectrometer may be a promising candidate for tissue hydration sensing and practical application of THz technology.
基金The Science and Technology Commission of Shanghai Municipality under Grant(16ZR1435000)
文摘THz Radar Cross Section(RCS)measurement setup based on THz Time Domain Spectroscopy(TDS)is built to provide large scaled targets test ability in recent years.As calibrations,the metal plates and dihedrons are used in our experiments.The measurements are performed in a monostatic terahertz time-domain setup.The author proposed time domain and frequency domain calibration methods for angular RCS of calibrations,comparing the measurements with the theory to verify the ability of the time domain measurement setup.
文摘Terahertz （THz） radiation, whose frequency ranges from 0.1 THz to 10.0 THz, has rich science, but limited technology. It has long been considered the last remaining scientific gap in the electromagnetic spectrum. Far from being fully exploited, it offers great opportunities in science, innovation, new technology, and potential applications. THz science and technology enables fundamental research directly impact our lives, from industrial quality control,
基金Supported by National Natural Science Foundation of China(Nos.10574134,10805068,and 60907044) and National Basic Research Program of China(No. 2010CB832903)
文摘Terahertz time-domain spectroscopy(THz-TDS)was utilized to investigate the solid-state reaction between L(+)-Tartaric acid and sodium hydrogen carbonate.Solid sodium hydrogen L(+)-tartrate monohydrate was synthesized efficiently by mechanical grinding,which is particularly sustainable and environmentally benign.Distinct THz absorptions were observed for pure reactants and the proposed product.The reaction process could be clearly visualized by THz spectral patterns of the reaction mixtures at different grinding time.The observed results were further confirmed by synchrotron radiation X-ray powder diffraction(SRXRPD)and Fourier transform infrared (FT-IR)spectroscopy.The study demonstrates that THz-TDS is an effective novel tool to monitor solid-state reactions in pharmaceutical industry.
基金the National Key R&D Program of China (No. 2018YFF01013003)the Program of Shanghai Pujiang Program, China (No. 17PJD028)+4 种基金the National Natural Science Foundation of China (Nos. 61671302, 61601291, and 61722111)the Shuguang Program supported by the Shanghai Education Development Foundation and Shanghai Municipal Education Commission, China (No. 18SG44)the Key Scientific and Technological Project of Science and Technology Commission of Shanghai Municipality, China (No. 15DZ0500102)the Shanghai Leading Talent, China (No. 2016-019)the Young Yangtse Rive Scholar, China (No. Q2016212).
文摘We give a brief review of the developments in terahertz time-domain spectroscopy(THz-TDS) systems and microcavity components for probing samples in the University of Shanghai for Science and Technology. The broadband terahertz(THz) radiation sources based on GaAs m-i-n diodes have been investigated by applying high electric fields. Then, the free space THz-TDS and fiber-coupled THz-TDS systems produced in our lab and their applications in drug/cancer detection are introduced in detail. To further improve the signal-to-noise ratio(SNR) and enhance sensitivity, we introduce three general micro-cavity approaches to achieve tiny-volume sample detection, summarizing our previous results about their characteristics, performance, and potential applications.
基金supported in part by the National Natural Science Foundation of China (Grant No 10874074)the Major State Basic Research Development Program of China (973 Program) (Grant Nos 2006CB601006 and 2007CB310404)PhD Programs Foundation of the Ministry of Education of China (200802840031)
文摘Terahertz(THz) time-domain spectroscopy(TDS) has been applied to investigate liquid's optical property in recent years.However,comprehensive discussion of how to compute liquids' complex refractive indices and absorption rates are seldom reported.So,in this work,we try to find a way to compute liquids' optical property accurately and conveniently.
基金supported by the National Natural Science Foundation of China (61302007 and 60977065)the Fundamental Research Funds for the Central Universities (FRF-SD12-016A)
文摘In this paper,we used terahertz time-domain spectroscopy(THz-TDS)over a range of 0.3–2.5 THz to investigate the formation of solid-state cocrystals of amino acids,formed by grinding mixtures of two different kinds of amino acids.For comparison,we prepared dual-layer samples,combined by pressing two single-component pellets together without grinding.In the ground-mixture samples,some extra absorption peaks appeared,different from the characteristic peaks of the pure components,but these peaks did not appear in the dual-layer samples.Thus,these extra absorption peaks in the THz range are unique features of cocrystals.From our results,we believe that THz-TDS is a promising technique to characterize cocrystals.
文摘In this paper, we employed terahertz time domain spectroscopy （THz-TDS） to investigate the nitrate 0 concentration in four types of nitrate solution （sodium nitrate, aluminum nitrate, calcium nitrate and magnesium nitrate）. Their absorption coefficient and refractive index were calculated in 0.2-2.5THz, and a logarithmic relationship was observed between NO3 concentrations and selected optical parameters regardless of the kinds of nitrate solution. Partial least square （PLS） model was built between THz-TDS and NO3 concentration. The correlation coefficient of PLS model was calculated. The results make the quantitative analysis of NO3 concentration possible by THz-TDS and indicate the bright future in practical application.
