نتایج جستجو برای: beams

تعداد نتایج: 33005  

Journal: :Applied optics 2014
Yana V Izdebskaya Ting-Hua Lu Dragomir N Neshev Anton S Desyatnikov

We study numerically and demonstrate experimentally a novel type of singular optical beams formed by the phase imprinting of an optical vortex into the structure of the three-Airy beams. In contrast to a vortex-free product of three Airy beams, in this type of singular-Airy beam, the vortex in the beam axis causes a twist in the beam transverse intensity profile with propagation. Such a new typ...

2005
S. J. H. Petra

We present a method to obtain power-balanced laser beams for doing quantum-state manipulation experiments with phase-stable double optical lattices. Double optical lattices are constructed using four pairs of overlapped laser beams with different frequencies. Our optical scheme provides a phase stability between the optical lattices of 5 mrad/s, and laser beams with a very clean polarisation st...

2012
Ozlem Kilic Amir I. Zaghloul

Due to bandwidth limitations in cellular communications, the same bandwidth is allocated to beams which are isolated spatially. This is known as frequency reuse, and the beams operating at the same frequency are referred as co-channel beams. While this approach allows a large coverage area with limited bandwidth, the co-channel beams have the potential to interfere with each other. This is know...

Journal: :Optics letters 2011
Peng Zhang Jai Prakash Ze Zhang Matthew S Mills Nikolaos K Efremidis Demetrios N Christodoulides Zhigang Chen

We observe optical trapping and manipulation of dielectric microparticles using autofocusing radially symmetric Airy beams. This is accomplished by exploiting either the inward or outward transverse acceleration associated with their chirped wavefronts. We experimentally demonstrate, for the first time to our knowledge, that such Airy beams morph into nondiffracting Bessel beams in their far-fi...

Journal: :Int. J. Imaging Systems and Technology 1997
Jian-yu Lu

Limited diffraction beams have a large depth of field infinite aperture. Because of their high side lobes and complex and could have many applications. In this article, new limited diffracbeam patterns near the cone surface, these devices are not curtion beams are developed. They are composed of multiple parallel rently used in clinics. Ring antenna [42] or transducer [43,44] is beams and are t...

2007
Grayson W. Marshall Sally J. Marshall

Objectives. The objective was to determine the fracture and cyclic fatigue properties of composite–dentin beams bonded with a self-etching adhesive in four-point bend. Methods. Beams of rectangular cross-section were shaped to a size of ∼0.87mm×0.87mm×10mm and placed in a four-point bending apparatus, with the loading points 1.8 and 7.2mm apart, with the interface centered between the inner rol...

2010
Brian P. Quaranta Shiva K. Das Timothy D. Shafman Kim L. Light Lawrence B. Marks

Traditional treatment beams for non-small-cell lung cancer are limited to the axial plane. For many tumor geometries, non-axial orientations appear to reduce the dose to normal tissues (e.g. heart, liver). We hypothesize that non-axial beams provide a significant reduction in incidental irradiation of the heart and liver, while maintaining adequate target coverage. CT scans of twenty-four patie...

2006
Y. Kuroda J. Yang T. Kondoh A. Yoshida

A concept of double-decker electron beams, which have vertically different positions and time delay, was proposed for study of ultra-fast electron-induced reactions or phenomena by pulse radiolysis technique. One of the double-decker electron beams is used as a pump source, and another is converted to Cherenkov light and used as a probe light source. The double-decker electron beams were genera...

2015
Jean-Paul Lebet

The mechanical response of post-tensioned glass beams is explored in this paper. This is done through bending experiments on post-tensioned glass beam specimens with either mechanically anchored or adhesively bonded steel tendons by which a beneficial pre-stress is inflicted on the glass beams. In addition, reference beams with identical geometry but without tendons are tested. From the results...

Journal: :Nature communications 2012
Patrice Genevet Jiao Lin Mikhail A Kats Federico Capasso

Metallic components such as plasmonic gratings and plasmonic lenses are routinely used to convert free-space beams into propagating surface plasmon polaritons and vice versa. This generation of couplers handles relatively simple light beams, such as plane waves or Gaussian beams. Here we present a powerful generalization of this strategy to more complex wave-fronts, such as vortex beams that ca...

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