The classical self-imaging effect can be observed for a periodic object with a pitch larger than the diffraction limit of an
imaging system. In this paper, we show that the self-imaging effect can be achieved in an indefinite metamaterial even
when the period is much smaller than the diffraction limit in both two-dimensional and three-dimensional numerical
simulations, where the paraxial approximation is not applied. This is attributed to the evanescent waves, which carry the
information about subwavelength features of the object, can be converted into propagating waves and then conveyed to
far field by the metamaterial, where the permittivity in the propagation direction is negative while the transverse ones are
positive. The indefinite metamaterial can be realized and approximated by a system of thin, alternating multilayer metal
and insulator (MMI) stack. As long as the loss of the metamaterial is small enough, deep subwavelength image size can
be achieved.
The Talbot effect (or the self-imaging effect) can be observed for a periodic object with a pitch larger than the diffraction
limit of an imaging system, where the paraxial approximation is applied. In this paper, we show that the super Talbot
effect can be achieved in an indefinite metamaterial even when the period is much smaller than the diffraction limit in
both two-dimensional and three-dimensional numerical simulations, where the paraxial approximation is not applied.
This is attributed to the evanescent waves, which carry the information about subwavelength features of the object, can
be converted into propagating waves and then conveyed to far field by the metamaterial, where the permittivity in the
propagation direction is negative while the transverse ones are positive. The indefinite metamaterial can be
approximated by a system of thin, alternating multilayer metal and insulator (MMI) stack. As long as the loss of the
metamaterial is small enough, deep subwavelength image size can be obtained in the super Talbot effect.
Due to the large transverse mode size in the frequency regime far below plasma frequency, some important applications
of surface plasmons in the THz or microwave frequency regime have been limited where deep subwavelength optical
devices are a critical technique. Here we experimentally demonstrated focusing and guiding electromagnetic (EM) waves
in a 3D spoof surface plasmonic waveguide, which is a row of rectangular rods patterned on an aluminum slab. The
maximum of the mode size can be mapped in the middle plane of two neighboring rods. The mode size slightly varies
with different frequencies and minimizes at 0.04λ-by-0.03λ at 2.25 GHz. Moreover, due to the tight binding of surface
waves, the decrease of the waveguide width does not significantly affect the dispersion of the guided modes. This fact
enables the mode tapering in the transverse direction from a wide waveguide into deep subwavelength waveguide with
high efficiency. To this end, a tapered spoof surface plasmonic waveguide was fabricated as the input is the uniform
spoof surface plasmonic waveguide and its performance was investigated in experiments. From the experimental results,
as the EM waves propagate in the taper, the mode size becomes smaller and smaller with the intensity gradually
increasing, and eventually EM waves are coupled into the deep subwavelength mode.
In this paper a coarse region segmentation of liver cancer in ultrasound Images is introduced. The reason employing coarse
region segmentation is to reflect the inhomogeneous distribution of the image gray levels and provide the features such as
the distribution, shape and size of the suspect region of liver cancer. Then combine with the prior knowledge we can divide
the image into three different classes, which the results of the analysis of the region's location can be used by a classifier in
a multilayer classifier. Furthermore, the result of the coarse region segmentation will support the texture analysis for
further classification. The segmentation is based on watershed algorithm in order to receive an integrated region and two
processing techniques are adopted to avoid the over segmentation of watershed algorithm.
Miniaturized on-chip optical isolators are highly desirable for advanced optical telecommunications to eliminate noise and protect the laser source. This talk will discuss the fabrication and testing of on-chip photonic crystals in ferrite waveguides. Photonic band gap engineering can produce Faraday rotators with highly enhanced polarization rotation for ultra-small integrated optical isolators. The main challenges to such devices are the elimination of linear birefringence and the efficient production of planar photonic band gap nanostructures. These challenges are addressed in the present article. In particular, we demonstrate the presence of stopbands and resonant polarization response in single-defect magneto-optic photonic crystal waveguides. However, waveguide birefringence degrades the magneto-optic response and results in significant ellipticity at resonance. Lower birefringence waveguides are required for enhanced magneto-optic performance.
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