1. |
- Ablikim, M., et al.
(author)
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Measurements of (XcJ)-> K+K-K+K- decays
- 2006
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In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:3, s. 197-202
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Journal article (peer-reviewed)abstract
- Using 14M psi(2S) events taken with the BESII detector, chi(cJ) -> 2(K+K-) decays are studied. For the four-kaon final state, the branching fractions are B(chi(c0,1,2) ->.2(K+K-)) = (3.48 +/- 0.23 +/- 0.47) x 10(-3), (0.70 +/- 0.13 +/- 0.10) x 10(-3), and (2.17 +/- 0.20 +/- 0.31) x 10(-3). For the phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi(c0,1,2) -> phi K+K-) = (1.03 +/- 0.22 +/- 0.15) x 10(-3), (0.46 +/- 0.16 +/- 0.06) x 10(-3), and (1.67 +/- 0.26 +/- 0.24) x 10(-4). For the phi phi final state, B(chi(c0,2) -> phi phi) = (0.94 +/- 0.21 +/- 0.13) x 10(-3) and (1.70 +/- 0.30 +/- 0.25) x 10(-3).
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2. |
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3. |
- Acciari, V. A., et al.
(author)
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Radio Imaging of the Very-High-Energy gamma-Ray Emission Region in the Central Engine of a Radio Galaxy
- 2009
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 325:5939, s. 444-448
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Journal article (peer-reviewed)abstract
- The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10(12) electron volts and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we report on radio and VHE observations of the radio galaxy Messier 87, revealing a period of extremely strong VHE gamma-ray flares accompanied by a strong increase of the radio flux from its nucleus. These results imply that charged particles are accelerated to very high energies in the immediate vicinity of the black hole.
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4. |
- Cui, Y., et al.
(author)
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Transmission enhancement of a metallic slit by a nearby metallic nano-particle
- 2008
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE.
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Conference paper (peer-reviewed)abstract
- We propose to use a nearby metallic nano-particle to greatly enhance the transmission efficiency of a nano-slit aperture in a metallic film. The metallic nano-particle helps to form a T shape cavity which could effectively transform the propagating incident light into localized near-filed light. Harvest efficiency is enhanced by 20 times for a non-resonant 25 nm-width nano-slit.
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5. |
- Cui, Y., et al.
(author)
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Transmission enhancement of light through a metallic nano-slit with periodic metallic nano-strips
- 2009
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In: Metamaterials IV. - : SPIE - International Society for Optical Engineering. - 9780819476272 ; , s. 73530S-
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Conference paper (peer-reviewed)abstract
- The study of the transmission properties of subwavelength apertures has become a very active area of research in electromagnetism. It is generally accepted that structuring the input surface of the metal film by periodic corrugations is very effective in the process of transmission enhancement through single apertures. Here instead of periodic corrugations, we propose to use periodic nano-strips placed before the input surface of the metal film to enhance the transmission of light through a nano-slit milled in the film. Influences of the structural parameters of periodic nano-strips on the transmission enhancement are investigated. The transmission efficiency through a 25nm-width silver nano-slit can be boosted to be ç = 164 when six pairs of nano-strips are placed 50nm distant away from the incident surface of the silver film at ë0 = 1ìm, which is originally ç = 7.8 without any strips. This indicates that a large part of the incident light can be transformed into the localized guided wave with strong intensity, and then more light can flow through the nano-slit. We emphasize that periodic nano-strips can serve as an efficient receiving antenna to harvest light into the nano-slit.
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6. |
- Cui, Y. X., et al.
(author)
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Giant Optical Transmission through a Metallic Nano-slit Achieved by the Optimization of the Groove Periodicity and Other Parameters
- 2008
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In: PROCEEDINGS OF THE 2008 INTERNATIONAL WORKSHOP ON METAMATERIALS. - NEW YORK : IEEE. - 9781424426089 ; , s. 236-239
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Conference paper (peer-reviewed)abstract
- The extraordinary optical transmission of light through a metallic nano-slit surrounded by groove corrugations can further be increased by optimizing the geometric parameters including the period of the corrugations, the period which has been set to be equal to the surface-plasmon wavelength in most of the previous works. By a global optimization, we are able to enhance the transmission efficiency of light through a silver nano-slit of 25 nm-wide as high as 18500 percent when the slit is surrounded by only 6 pairs of grooves.
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7. |
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8. |
- Cui, Y. X., et al.
(author)
-
A theoretical re-examination of giant transmission of light through a metallic nano-slit surrounded with periodic grooves
- 2009
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In: Optics Express. - 1094-4087. ; 17:16, s. 13995-14000
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Journal article (peer-reviewed)abstract
- We show that the slit-to-groove distance for a maximal transmission through the nano-slit surrounded with periodic grooves cannot be predicted by the theory of constructive interference between the groove-generated surface plasmon wave (SPW) and the incident wave. A clear physical explanation is given for the dependence of the transmission on the slit-to-groove distance. It is shown that the influence to the transmission comes from three parts: the groove-generated SPW, the incident wave and the nano-slit-generated SPW. The groove-generated SPW is the main factor determining the local field distribution around the nano-slit opening. The influence of the incident wave is very weak when strong SPW is generated on the input surface by many periods of deep grooves. The nano-slit-generated SPW can also be considered as a disturbance to the light distribution on the input surface.
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9. |
- Cui, Y. X., et al.
(author)
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Enhancing extraordinary transmission of light through a metallic nanoslit with a nanocavity antenna
- 2009
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In: Optics Letters. - 0146-9592 .- 1539-4794. ; 34:1, s. 16-18
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Journal article (peer-reviewed)abstract
- The extraordinary transmission of light through a vertical nanoslit in a metal film is enhanced by introducing a nanocavity antenna formed by a nearby metallic nanostrip over the slit opening. For a fixed wavelength, the width of the metallic nanostrip should be chosen to make the horizontal metal-insulator-metal waveguide of finite length resonant as a Fabry-Perot cavity. When such a cavity antenna is used to enhance the transmission through a nonresonant nanoslit, the slit should be opened at a position with a maximal magnetic field in the horizontal resonant cavity. It is shown that an optimized cavity antenna can enhance greatly the transmission of light through a nonresonant nanoslit (by about 20 times) or a resonant nanoslit (by 124%). Such a transmission enhancement with a nanocavity antenna is studied for the first time, and the physical mechanism is explained.
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10. |
- Cui, Y. X., et al.
(author)
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Nanocavity antenna array for enhancing extraordinary optical transmission of light through a metallic nanoslit
- 2009
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In: Journal of the Optical Society of America. B, Optical physics. - 0740-3224 .- 1520-8540. ; 26:11, s. 2131-2135
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Journal article (peer-reviewed)abstract
- The transmission of light through a single nanoslit milled in the metallic film is enhanced by using an array of nanocavity antennas. It is shown that transmission efficiency through a 25-nm-wide silver nanoslit can be enhanced to eta = 151 when six pairs of nanostrips are placed 50 nm away from the input surface of the silver film at wavelength lambda(0) = 1 mu m. The influences of both the nanoslit position and the slit-to-strip distance on the extraordinary transmission are investigated, and the physical mechanism is explained.
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