共查询到20条相似文献,搜索用时 0 毫秒
1.
Yiping Tang Xingguo Li Zhenfa Luo Guozhen Li 《International Journal of Infrared and Millimeter Waves》1997,18(4):827-846
This paper researches mainly the radiation characteristics of the target and detecting techniques by superconducting detector
in the submillimeter wave(SMMW) region. The calculation of transition wavelength(TW) between Planck and Rayleigh-Jeans is
given out. The experiment of detecting different targets is finished by use of superconducting detector possessing high performances.
Through the experiments in paper we can select and determine the wave bands of SMMW detecting and imaging system. The many
novel theoretical analyses and experimental results are expressed in Figs and tables of the paper. Finally, a part of calculating
results and experimental datum detected by a superconducting detector in SMMW regions are given in this paper. 相似文献
2.
Based on the multi-coincidence measurement, the time resolution of three liquid scintillation detectors (BC501A) were determined strictly by solving the coincidence equations, where the influence from electronics estimated by self coincidence measurement as well as the background had been considered. The result of this work agreed well with the result that was deduced from the traditional method, and it will be helpful to analyze the energy resolution of neutron time of flight spectra measured by using such detectors at CIAE (China Institute of Atomic Energy). 相似文献
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Based on the multi-coincidence measurement, the time resolution of three liquid scintillation detectors (BC501A) were determined strictly by solving the coincidence equations, where the influence from electronics estimated by self coincidence measurement as well as the background had been considered. The result of this work agreed well with the result that was deduced from the traditional method, and it will be helpful to analyze the energy resolution of neutron time of flight spectra measured by using such detectors at CIAE (China Institute of Atomic Energy). 相似文献
4.
P. Kopyt B. Salski A. Pacewicz P. Zagrajek J. Marczewski 《Opto-Electronics Review》2019,27(2):123-129
This article describes a novel approach to measure responsivity of a FET-based sub-THz detector using on-wafer probes to directly feed a bare antenna-less detecting device. Thus, the approach eliminates the need to know beforehand the detector’s effective aperture, which can be a source of large variation between responsivity measurements of various FET-based detectors often cited in the literature. It seems that the presented method can be useful at making direct comparisons between responsivity of various devices (e.g., MOSFETs, HEMTs etc.). As a demonstration, the sub-THz responsivity of a pHEMT device fabricated using a commercial GaAs process has been measured in a WR-3 frequency band. Additionally, the results have been compared against data obtained using an alternative approach. The verification method consisted in integrating exactly the same device with a broad-band antenna and a carefully selected high-resistivity silicon lens and comparing its performance with that of a commercial calibrated detector based on Schottky diodes. 相似文献
5.
Near-field Scanning Optical Microscopy (NSOM) is a powerful tool for investigating optical field with resolution greater than
the diffraction limit. In this work, we study the spectral response that would be obtained from an aperture NSOM system using
numerical calculations. The sample used in this study is a bowtie nanoaperture that has been shown to produce concentrated
and enhanced field. The near- and far-field distributions from a bowtie aperture are also calculated and compared with what
would be obtainable from a NSOM system. The results demonstrate that it will be very difficult to resolve the true spectral
content of the near-field using aperture NSOM. On the other hand, the far-field response may be used as a guide to the near-field
spectrum. 相似文献
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The most important sources of error incurred in the measurements of spectral-line parameters arise from uncertainty in the determination of the 100 per cent transmittance and in the distortion of the line profile by the spectrometer. These errors have been investigated numerically by passing an idealized spectrometer slit function over several assumed line profiles. In this way, families of correction curves have been constructed, from which spectral-line strengths, widths, and peak absorption coefficients may be determined from apparent values measured directly from the chart recorder. The effect of the form of the slit function has been investigated by using triangular, Gauss, Cauchy and combination Gauss-Cauchy slit functions. The effect of uncertainties in the line shape has been investigated by using Doppler, Lorentz, and Voigt line shapes. 相似文献
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Homodyne method of measurement of polarization reflection matrix, providing the possibility of simultaneous measurement of all four complex coefficients of polarization reflection matrix in submillimeter quasi-optical (QO) circuits is presented. Technical realizability of the method for QO waveguides of the class of "hollow dielectric wavequide" is shown. 相似文献
8.
<正>The dispersion of Yb-doped fiber is measured by a spectral interferometric technique.The experimental verification is achieved by comparing the measured data with published data of the Nufern 1060xp fiber and the measurement relative error is 1.36%.The parameters of the experimental system,such as minimum required source bandwidth and minimum fiber length,are introduced and analyzed in the measurement. The minimum required source bandwidth predicted through theoretical calculation at the center wavelength of 1070 nm is 19.3 nm,which perfectly agrees with the experimental value. 相似文献
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The spectral dynamics of individual bacterial light-harvesting-2 pigment-protein complexes have been studied at 1.4 K. The data provided the spectral diffusion kernel of the optical transitions of the embedded B800 bacteriochlorophyll a pigments. This kernel can be described by either a single Gaussian function or a superposition of Gaussian functions. Moreover, we found that the chromophores interact with two classes of TLSs that can be distinguished by their distance from the chromophore and are most likely located outside (class 1) and inside (class 2) the protein matrix. 相似文献
11.
K. Vetter 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):265-269
Gamma-ray tracking in a closed array of highly segmented HPGe detectors is a new concept for the detection of γ-radiation.
Each of the interacting γ-rays is identified and separated by measuring the energies and positions of individual interactions
and by applying tracking algorithms to reconstruct the scattering sequences, even if many γ-rays hit the array at the same
time. The three-dimensional position and the energy of interactions are determined by using two-dimensionally segmented Ge
detectors along with pulse-shape analysis of the signals. Such a detector will have new and much improved capabilities compared
to current γ-ray spectrometer. One implementation of this concept, called GRETA (Gamma-Ray Energy Tracking Array), is currently
being under development at LBNL.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: kvetter@lbl.gov 相似文献
12.
We analyze both theoretically and experimentally the temporal response of a stimulated Brillouin scattering generator to an harmonically modulated pump beam in a 2.1 km optical fiber. It is shown that at certain frequencies (where m is an integer number and are frequencies which depends mainly on the fiber’s length L but also on the beam’s intensity via G) the first harmonic of the generated Stokes beam is relatively suppressed but never vanishes. These frequencies are considerably smaller than the Brillouin’s spectral width (∼20 MHz). Excellent agreement with the analytical model is presented. 相似文献
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T. Idehara K. Yoshida N. Nishida I. Ogawa M. L. Pereyaslavets T. Tatsukawa 《International Journal of Infrared and Millimeter Waves》1998,19(6):793-801
The first cw operation of our submillimeter wave gyrotron (Gyrotron FU IV) using a 12 T superconducting magnet has been successfully carried out. Output power is more than 20 W at a frequency of 301 GHz in the TE031 resonant cavity mode. Time-resolved frequency measurement s shows that the frequency fluctuation of the gyrotron output is smaller than 2 MHz. This frequency fluctuation is mainly due to the fluctuation in the output voltage of the power supply. 相似文献
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The photon helicity may be mapped to a spin-1/2, whereby we put forward an intrinsic interaction between a polarized light beam as a "photon spin current" and a pure spin current in a semiconductor, which arises from the spin-orbit coupling in valence bands as a pure relativity effect without involving the Rashba or the Dresselhaus effect due to inversion asymmetries. The interaction leads to linear and circular optical birefringence, which are similar to the Voigt effect and the Faraday rotation in magneto-optics but nevertheless involve no net magnetization. The birefringence effects provide a direct, nondemolition measurement of pure spin currents. 相似文献
20.
In this study a novel method for determining surface flatness based on spectral interferometry is reported. In the traditional method a laser is used to produce intensity interference fringes and by measuring the shift in the position of a fringe when a test plate is put on a reference plate, the surface flatness of the test plate is determined. In the present study we have used a broad-band source for determining the flatness of a test plate. By studying the changes in the spectrum of the source on interference that are produced when a test plate is put on a reference plate, the surface flatness is determined. It has been found that the surface flatness determined by spectral studies comes out to be of the same order as that with a quasi-monochromatic laser light. This method might provide an edge over the present method by reducing the time taken in the study and also provide a cost-effective solution. 相似文献