نتایج جستجو برای: beams

تعداد نتایج: 33005  

2017
Yiqi Zhang Hua Zhong Milivoj R. Belić Yanpeng Zhang

Owing to the nondiffracting, self-accelerating, and self-healing properties, Airy beams of different nature have become a subject of immense interest in the past decade. Their interesting properties have opened doors to many diverse applications. Consequently, the questions of how to properly design spatial manipulation of Airy beams or how to implement them in different setups have become impo...

2008
Miroslav Pardy

We find the solutions of the Dirac equation for two plane waves (laser beams) and we determine the modified Compton formula for the scattering of two photons on an electron. The practical meaning of the two laser beams is, that two laser beams impinging on a target which is constituted from material in the form a foam, can replace 100-200 laser beams impinging on a normal target and it means th...

2005
Miroslav Pardy

We find the solutions of the Dirac equation for two plane waves (laser beams) and we determine the modified Compton formula for the scattering of two photons on an electron. The practical meaning of the two laser beams is, that two laser beams impinging on a target which is constituted from material in the form a foam, can replace 100-200 laser beams impinging on a normal target and it means th...

2008
M V Berry K T McDonald Joseph Henry

Energy trajectories, that is, integral curves of the Poynting (current) vector, are calculated for scalar Bessel and Laguerre-Gauss beams carrying orbital angular momentum. The trajectories for the exact waves are helices, winding on cylinders for Bessel beams and hyperboloidal surfaces for Laguerre-Gauss beams. In the geometrical-optics approximations, the trajectories for both types of beam a...

Journal: :Optics letters 2007
Sergey A Ponomarenko Weihong Huang Michael Cada

We present dark and antidark diffraction-free beams and discuss their properties. We show that all such beams must be partially spatially coherent. The new beams can be used for optical trapping of atoms.

Journal: :Radiation protection dosimetry 2009
Oliver Jäkel

Charged particle beams offer an improved dose conformation to the target volume when compared with photon radiotherapy, with better sparing of normal tissue structures close to the target. In addition, beams of heavier ions exhibit a strong increase of the linear energy transfer in the Bragg peak when compared with the entrance region. These physical and biological properties make ion beams mor...

2015
Juanying Zhao Ioannis D. Chremmos Daohong Song Demetrios N. Christodoulides Nikolaos K. Efremidis Zhigang Chen

For decades, singular beams carrying angular momentum have been a topic of considerable interest. Their intriguing applications are ubiquitous in a variety of fields, ranging from optical manipulation to photon entanglement, and from microscopy and coronagraphy to free-space communications, detection of rotating black holes, and even relativistic electrons and strong-field physics. In most appl...

2017
Yangsheng Yuan Ting Lei Zhaohui Li Yangjin Li Shecheng Gao Zhenwei Xie Xiaocong Yuan

Optical beam wander is one of the most important issues for free-space optical (FSO) communication. We theoretically derive a beam wander model for Bessel beams propagating in turbulent atmosphere. The calculated beam wander of high order Bessel beams with different turbulence strengths are consistent with experimental measurements. Both theoretical and experimental results reveal that high ord...

A. Kaveh, F. Shokohi,

The main object of this research is to optimize an end-filled castellated beam. In order to support high shear forces close to the connections, sometimes it becomes necessary to fill certain holes in web opening beam. This is done by inserting steel plates and welding from both sides. Optimization of these beams is carried out using three meta-heuristic methods involves CSS, CBO, and CBO-PSO al...

2015
Nivedita Mishra Hardeep Singh

Partially coherent Lorentz-Gauss beams can propagate by remaining spatially localized and non-divergent. The Gaussian beams and after a bit application of Lorentz function, the Lorentz-Gauss beams are a better tool for optical communication. Analytical formulae for spatial complex degree of coherence are derived. In this paper mathematical model of Lorentz-Gauss beams is derived in terms of ABC...

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