共查询到20条相似文献,搜索用时 0 毫秒
1.
M. I. Volobuev S. B. Karamyshev R. D. Mukhamedyarov R. Sh. Usmanov 《Journal of Applied Spectroscopy》1992,56(1):103-105
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 56, No. 1, pp. 159–161, January, 1992. 相似文献
2.
A. K. Bakarov A. K. Gutakovskii K. S. Zhuravlev A. P. Kovchavtsev A. I. Toropov I. D. Burlakov K. O. Boltar’ P. V. Vlasov A. A. Lopukhin 《Technical Physics》2017,62(6):915-919
The MBE method has been applied to grow InSb layers on InSb substrates. These layers have served as a basis for fabricating mid-wave IR photodetector arrays. The characteristics of photodetector arrays on epitaxial InSb layers have been compared with those of series-produced single-crystal InSb arrays. 相似文献
3.
We report a demonstration video-rate heterodyne holography in off-axis configuration. Reconstruction and display of a one megapixel hologram is achieved at 24 frames per second, with a graphics processing unit. Our claims are validated with real-time screening of steady-state vibration amplitudes in a wide-field, noncontact vibrometry experiment. 相似文献
4.
Synthetic-aperture experiment in the visible with on-axis digital heterodyne holography 总被引:3,自引:0,他引:3
We have developed a new on-axis digital holographic technique, heterodyne holography. The resolution of this technique is limited mainly by the amount of data recorded on two-dimensional photodetectors, i.e., the number of pixels and their size. We demonstrate that it is possible to increase the resolution linearly with the amount of recorded data by aperture synthesis as done in the radar technique but with an optical holographic field. 相似文献
5.
Three-dimensional location of fluorescent inhomogeneities in turbid media by scanning heterodyne holography 总被引:1,自引:0,他引:1
We describe and illustrate experimentally a method aimed at the three-dimensional (3-D) imaging of fluorescent inhomogeneities embedded in a turbid medium. The method utilizes incoherent scanning holography to capture 3-D information in a single two-dimensional scan and phase-sensitive heterodyne detection to reject multiply scattered light and to produce a single-sideband holographic record. The 3-D imaging capability of the method is illustrated by an example. 相似文献
6.
SB349 is the first 32 × 32 CTIA readout multiplexer specifically designed for far-IR photodetectors and is operable at cryogenic temperatures at least as low as 1.7 K. Four of these readouts can be butted together to form a 64 × 64 mosaic array. The array is multiplexed into eight parallel outputs and features eight selectable gain settings to accommodate various background levels, auto-zero for better input uniformity, and sample-and-hold circuitry. A special, 2-micron cryo-CMOS process was adopted to prevent freeze out and ensure low noise and proper operation at deep cryogenic temperatures. The read noise of the bare device at 4.2 K and under nominal sampling conditions was measured to be about 250e? for the 106fF signal capacitor with the well capacity of 400ke?. Hybridized to a typical germanium detector, the array should achieve NEP levels in the low 10–18 W/√Hz. An overview of the design and the latest results of the test and characterization of this device are reported in this paper. 相似文献
7.
Kuniaki Nagayama 《Phase Transitions》2013,86(2-3):185-203
We report the effective fabrication of two-dimensional (2D) arrays of submicron colloidal particles. These colloidal arrays are produced in thin layers of monodisperse colloid suspensions on flat surfaces of solids such as clean glass or cleaved mica. The process of colloid assembling includes two steps, nucleation and growth, similar to those found in crystallization in solution but each of the steps in detail progresses with different mechanisms. The nucleation process is initiated by a special kind of capillary force acting parallel to the surface. The growth is guided by a laminar flow of water to the crystals, which is driven by water evaporation from 2D arrays. What is distinguishable in the 2D assembling is its active nature governed by the forces and flows, making a contrast to the diffusive mechanism in ordinary crystallization. With this two-step mechanism, a domain of hexagonally packed colloidal array can grow with time. A large and uniform film of particle monolayer is, thus, formed in a short period, from several seconds up to several minutes depending on the conditions controlled. 相似文献
8.
Schemes for recording and reconstruction of relief-phase reflection holograms providing virtually aberration-free imaging of the structure of two-dimensional objects were developed and substantiated. Samples of relief-phase reflection holograms forming a speckle-free image of a photolithographic test pattern with a characteristic size of 0.8 μm at a wavelength of 0.488 μm with a numerical aperture of 0.6 were obtained on a layer of recording medium (chalcogenide deposited on a plane glass substrate). On the basis of the results obtained, it was concluded that it is practically possible to attain the diffraction limit of hologram resolution and that further studies aimed at the implementation of methods of optical holography into photolithography and, predominantly, into short-wavelength ultraviolet lithography, are undoubtedly promising. 相似文献
9.
K. A. Grebenyuk 《Optics and Spectroscopy》2017,123(2):200-204
It is established, that in modern works on digital holography, three fundamentally different mathematical models of a matrix photodetector are used. Comparative analysis of these models, including analysis of the formula of each model and test calculations, has been conducted. The possibility of using these models to account for the influence of geometrical parameters of a matrix photodetector on the properties of recorded digital holograms is considered. 相似文献
10.
L. T. Little S. R. Davies 《International Journal of Infrared and Millimeter Waves》1994,15(6):935-942
The construction of SIS heterodyne imaging arrays for submillimetre wave-lengths requires multiple coupling of the local oscillator signal. The quasi-optical analogue of a multiple cross-guide coupler, employing 45° beam-splitters successively stacked along the local oscillator beam, allows for individual adjustment of local oscillator power to each channel. We analyse the coupling as a function of the focal ratio of the incident beams and the number of beam widths off-axis through which the coupler is extended, and describe a simple construction method to realise a compact and effective design. 相似文献
11.
Nanoantennas have the unique ability to affect the emission pattern of a dipole in free space. We present a technique based on full-field heterodyne holography for the mapping of the scattered field of plasmonic gold nanodisk chains in all three dimensions. A spectroscopic study allowed us to determine the resonant and nonresonant wavelengths at which we conducted a full characterization of the scattered field on a chosen nanodisk chain. 相似文献
12.
Xianghui Zhang Xiangyun Han Jun Su Qi Zhang Yihua Gao 《Applied Physics A: Materials Science & Processing》2012,107(2):255-260
Well-crystallized ZnO nanowire arrays were grown on GaN/sapphire by one-step chemical vapor deposition under control of the
fabrication pressure of 1000–2500 Pa and the best-aligned arrays were obtained at 1000 Pa. A photoluminescence study shows
a red shift with nanowire diameter increase. Under 365-nm UV irradiation of 0.3 mW/cm2, the photoresponse study of the best ZnO arrays shows an ultra-fast tri-exponential rise with three constants of 0.148, 0.064
and 0.613 s, and a bi-exponential decay behavior with two recovery constants of 30 and 270 ms. The ZnO/GaN heterojunction
barriers could be responsible for the ultra-fast tri-exponential rise and bi-exponential decay behavior. 相似文献
13.
Alexandru Nedelcu Vincent Guériaux Alexandre Bazin Lydie Dua Arnaud Berurier Eric Costard Philippe Bois Xavier Marcadet 《Infrared Physics & Technology》2009,52(6):412-418
A 30 months European Space Agency project started in March 2008, whose overall purpose is to expand and assess the performance of broadband (11–15 μm) quantum detectors for spectro-imaging applications: Dispersive Spectrometers and Fourier Transform Spectrometers. We present here the technical requirements, the development approach chosen as well as preliminary experimental results. Our approach is fully compatible with the final array format (1024 × 256, pitch 50–60 μm). We expect the requested uniformity, operability and SNR levels to be achieved at temperatures close to the goal values. The performance level will be demonstrated on 256 × 256, 50 μm pitch arrays. Also, operability and uniformity issues will be addressed on large mechanical 1024 × 256 hybrid arrays. 相似文献
14.
Mazo JJ 《Physical review letters》2002,89(23):234101
We have proposed theoretically and studied numerically the existence of discrete breathers (intrinsic localized modes) in the dynamics of a two-dimensional Josephson-junction array biased by radio-frequency fields. The solutions are linearly stable in the framework of the Floquet theory and robust in the presence of thermal fluctuations. We have also discussed the conditions for realizing an experimental detection of these modes. 相似文献
15.
An optical system for the parallel evaluation of in- and out-of-plane dynamical deformations will be described. A double pulse laser with pulse separation in the microsecond range is used for the investigations. Two separate interferograms of an object under test, in its undeformed and deformed state, are recorded in a few microseconds. The object is illuminated from two different directions and imaged onto a CCD sensor. This produces two sensitivity vectors. The reference beams have different directions in order to produce two directional spatial carriers. The Fourier method is used for quantitative evaluation, and the measurements along different sensitivity vectors are separated in the Fourier domain. The phases of the two interferograms are obtained from the complex amplitudes and the two dimensional deformation is calculated from the phases. Experimental results are presented. 相似文献
16.
A two-dimensional heterodyne detection technique based on the frequency-synchronous detection method [Jpn. J. Appl. Phys. 39, 1194 (2000)] is demonstrated for full-field optical coherence tomography. This technique, which employs a pair of CCD cameras to detect the in-phase and quadrature components of the heterodyne signal simultaneously, offers the advantage of phase-drift suppression in interferometric measurement. Horizontal cross-sectional images are acquired at the rate of 100 frames/s in a single longitudinal scan, with a depth interval of 6 microm, making the rapid reconstruction of three-dimensional images possible. 相似文献
17.
Electromagnetic interaction of fluorophores with designed two-dimensional silver nanoparticle arrays 总被引:1,自引:0,他引:1
H. Ditlbacher N. Felidj J.R. Krenn B. Lamprecht A. Leitner F.R. Aussenegg 《Applied physics. B, Lasers and optics》2001,73(4):373-377
We study the fluorescence enhancement of dye molecules adsorbed on regular two-dimensional arrays of designed silver nanoparticles.
The silver particles show two orthogonal optical resonances at different wavelengths because of their elongated shape. The
short-wavelength resonance was designed to fit to the absorption maximum of the fluorophore. When the excitation light drives
the short-wavelength resonance, the measured fluorescence intensity is strongly enhanced compared to that for the orthogonal
particle orientation. This shows directly a strong electromagnetic coupling between the nanoparticles and the fluorophore.
Additionally enhanced photochemical bleaching is observed due to the interaction of fluorophores with the particles. Using
a rate model describing the fluorescence enhancement and the bleaching enhancement, an average value for the particle-induced
increase in the radiative fluorescence rate is obtained, together with a lower limit for the averaged particle-induced field
intensity enhancement factor.
Received: 3 July 2001 / Revised version: 3 September 2001 / Published online: 15 October 2001 相似文献
18.
We propose a temporal holography technique for realizing matched filter structures for arbitrary, narrow-band optical signals. By utilizing the extraordinarily large angular dispersion of a fiber-optic tapped delay line array, we show that it is possible to achieve temporal filtering of optical signals whose coherence times can exceed nanoseconds. This represents a significant improvement in the temporal reach of holographic filters, compared to grating-based methods. 相似文献
19.
The structure of oriented 2D block copolymer single crystals is characterized by grazing-incidence small-angle x-ray diffraction, demonstrating long-range sixfold orientational order. From line shape analysis of the higher-order Bragg diffraction peaks, we determine that translational order decays algebraically with a decay exponent eta=0.2, consistent with the Kosterlitz-Thouless-Halperin-Nelson-Young theory for a 2D crystal with a shear modulus mu=2 x 10(-4) N/m. 相似文献