Alan Tomlinson, John Dugdale, Edward BURRELL(Chairman), Jon Ashworth, Denis VAUGHAN(Executive Director), Victoria Glendinning, David Tytler, Nick Nuttall, Maj Sjovall & Per Wahloo, Lisanne Radice, Anatol Lieven, David Canter, Patricia Davies, W. Dixon Smith, Garry Pownall, Bill Abbotts, Simon Barnes, Sheila Gunn, Political Correspondent, John Ambrose, A. J. E. Kingshott, Angela MacKay, Robin Oakley, George Sivell, Noel Goodwin, Carol Leonard, Wolfgang Münchau, European Business Correspondent, Harry Eyres, Stuart Jones Football Correspondent, Michael McCarthy, Geoff Brown, D. Cuthbert, Ray Clancy, Bernard Levin, Martin Briggs, Robert Preston, Mitchell Platts, Golf Correspondent, Robert Reiner, Bruce Clark, Peter Stothard, US Editor, Dell Shannon, Philip Webster, Chief Political Correspondent, and Anatole Kaletsky, Economics Editor, Alfred Sherman, Peter Ball, Alan Lorimer, Clare Hogg, Louise Taylor, Richard Evans, Racing Correspondent, Robert Seely, Martin Barrow, Michael Evans, Defence Correspondent, Ray Kennedy, Alan Hamilton, Robert Nye, Stanley Hill, Michael Clark, Douglas Broom, Local Government Correspondent, Keith Pike, Philip Bassett, Industrial Editor, Philip Bassett, Gavin Bell, John Woodcock, Caithness, Dennis Signy, Lin Jenkins, Geoffrey Wheeler, Christopher Goulding, Richard Ottaway, Catherine Sampson, Kerry Gill, Jonathan Prynn, Alan Lee, Cricket Correspondent, Raymond Keene, Chess Correspondent, K. J. Waterfield, R. H. C. Heptinstall, Chris Partridge, Beryl Dixon, Nigel Hawkes, Heather Kirby, George Bickerstaffe, Peter T. Landsberg, Maeve Sherlock, Christopher Walker and Martin Fletcher, Roger Boyes, Graham Searjeant and Susan Ellicott, Ian Ross, Thomas Ginsberg of Associated Press, David Hands Rugby Correspondent, Michael Dynes, Transport Correspondent, Richard Duce, Peter Robeson, David Young, Ross Tieman Industrial Correspondent, Guy Yeoman, Sara McConnell, N. Butt, Brian Alderson, Colin Narbrough, Economics Correspondent, Mel Webb, Srikumar Sen Boxing Correspondent, Clive White, Associated Press, David Gullick, Michael Austin, John Bell, Business Editor, Irene McGrath, Philip Webster, Adrian Dannatt, William Cash, Michael Horsnell, Frances Gibb Legal Affairs Correspondent, L. Robertson, Benedict Nightingale, Quentin Cowdry, Home Affairs Correspondent, Dr Thomas Stuttaford, Derek Severs, David Tytler, Education Editor, Richard Morrison, Jack Bailey, W. S. Parker, Matthew Bond, Simon Weir, Philip Jacobson, Andrew Longmore, Tennis Correspondent, M. S., Mary Dejevsky, David A. Webb, John Watson,
... Man Victor Hochhauser Tilmann Wick Cello Heasook Rhee Plano Autumn Season Versatile but single-minded Cinema: Interview ... Diary From Red to Amber Reshaping South Africa Orbital Nonsense Hong Kong anger at Major accord TV ...
1991 - Gale Group | TDA
... circumbinarios) con planos orbitales muy inclinados relativo al plano orbital del sistema binario. Si las órbitas de estos ...
Tópico(s): Stellar, planetary, and galactic studies
2019 - | Revista de la Escuela de Física
Produção Nacional
Mário Antonio Alves Monteiro, Afonso Holanda de Freitas Freire, Cícero Jailton de Morais Souza, Giselly Alexandre de Souza, Ibson José Maciel Leite,
... e não levamos em consideração a inclinação do plano orbital da Lua. No entanto, mesmo com estas aproximações, ...
Tópico(s): Historical Geography and Cartography
2018 - | Revista Latino-Americana de Educação em Astronomia
Patrick Ruffieux, Toralf Scharf, Hans Peter Herzig, R. Völkel, K. J. Weible,
The optical properties of plano-convex refractive microlenses with low Fresnel Number (typically FN < 10) are investigated. It turns out that diffraction effects at the lens aperture limit the range of the effective focal length. The upper limit of the focal length is determined by the diffraction pattern of a pinhole with equal diameter. In addition achromatic microlenses can be realized because refraction and diffraction have opposing effects on the focal length. Gaussian beam propagation method ...
Tópico(s):
2006 - Optica Publishing Group | Optics Express
Numerical calculation of vector electromagnetic modes of plano-concave microcavities reveals that the polarization-dependent reflectivity of a flat Bragg mirror can lead to unexpected cavity field distribution for nominally paraxial modes. Even in a rotationally symmetric resonator, certain pairs of orbital angular momenta are necessarily mixed in an excitation-independent way to form doublets. A characteristic mixing angle is identified, which even in the ...
Tópico(s): Plasmonic and Surface Plasmon Research
2004 - Optica Publishing Group | Optics Letters
We consider, in an apertured plano-concave cavity, the TEM(00)-mode loss variations with mirror curvature. We define an effective beam truncation, taking into account the shrinking or widening of the beam that is due to the diffractive lens effect of the aperture.
Tópico(s):
1993 - Optica Publishing Group | Optics Letters
María Cecilia Fucini, Judith Ethel Baudo, A.C. Bencini, L.A. Sosa, Liliana Etchegoyen, C.G. Fornés, L. Solari, Edith I. Milat,
... tres calcos tomando como referencia estructuras en tres planos diferentes: A (orbital), B (maxilar) y C (mandibular).Se trazó una línea media virtual que se comparó con la línea media real.Plano frontal: Los resultados indicaron una mayor frecuencia de ...
Tópico(s): Orthodontics and Dentofacial Orthopedics
2009 - | Revista Española de Cirugía Oral y Maxilofacial
Bing Yan, Liyang Yue, James N. Monks, Xibin Yang, Daxi Xiong, Chunlei Jiang, Zengbo Wang,
A low-cost compound super-resolution lens, consisting of a Plano-Convex lens and a Microsphere lens (PCM), was proposed and demonstrated for subwavelength direct laser scanning writing application. The PCM lens can achieve a far-field super-resolution of ~{\lambda}/3.5 in air (~6 um away from lens) which surpasses resolution limit of existing commercial objective lenses and is the first of its kind. Arbitrary nano-patterns can now be directly fabricated on various substrates in a simpleand low-cost manner ...
Tópico(s):
2020 - Optica Publishing Group | Optics Letters
David L. Shealy, John A. Hoffnagle,
A review of the design and analysis of plano-aspheric laser beam shapers is presented. Both the Galilean and Keplerian configurations of the two aspheric lens laser beam shaper have been used and offer benefits for different applications. The geometrical optics based design methods of Kreuzer have been used to obtain a uniform output irradiance distribution with a gradual roll-off from the uniform to null region, which increases the distance over which the uniform irradiance distribution can be ...
Tópico(s):
2012 - SPIE | Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
A. Ghaffar, Qaisar Abbas Naqvi, Kazuhiro Hongo,
High frequency fields refracted by a geometry, which contains a plano-convex lens placed at a certain distance from a plane uniaxial interface, are derived by using Maslov's method. Maslov's method predicts the field in the caustic region by combining the simplicity of ray and generality of the transform method. Numerical computations are made for the field pattern around the caustic. The results are found in good agreement with results obtained using Kirchhoff's approximation.
Tópico(s):
2008 - Taylor & Francis | Journal of Electromagnetic Waves and Applications
A pair of plano-aspheric lenses can be used to transform a collimated, radially symmetric, Gaussian beam to a radially symmetric flat-top beam. Diffraction of the output beam due to the choice of irradiance profile, as well as the finite aperture of the optics, must be considered if a propagating beam is required. Choosing both lenses to be positive, one can show that the aspheric surfaces are strictly convex, which facilitates fabrication by magnetorheological figuring. A fused silica lens pair ...
Tópico(s): Electrowetting and Microfluidic Technologies
2003 - SPIE | Optical Engineering
A. Ghaffar, Qaisar Abbas Naqvi,
A three dimensional plano-convex lens which is placed at a certain distance from a plane uniaxial interface has been considered. High frequency fields refracted by the geometry are derived. The treatment is based on Maslov's method. The method combines the simplicity of asymptotic ray theory and generality of the transform method to remedy the problem of geometrical optics around the caustic point of a focusing system. Field patterns are obtained which includes the observation points around the ...
Tópico(s): Metamaterials and Metasurfaces Applications
2008 - | Electromagnetic waves
The closed trajectories of a Gaussian beam in plano–spherical degenerate and nondegenerate resonators with two Gaussian apertures (with two pump regions with the Gaussian distribution of the gain) are described analytically and the existence conditions are found for such trajectories. It was assumed that Gaussian apertures (gain regions) were located in the plane of a flat mirror at equal distances on both sides of the resonator axis and the size of apertures restricted their action by the corresponding ...
Tópico(s):
2008 - Institute of Physics | Quantum Electronics
M. P. Thirugnanasambandam, Yuri V. Senatsky, K. Ueda,
The use of a simple short-focus plano-convex glass lens with strong spherical aberration for Laguerre-Gaussian mode selection in a continuous wave (CW) LD-end-pumped Yb:YAG ceramic laser is demonstrated. Mode selection was obtained in a nearly meter long plane-parallel cavity by shifting an intra-cavity lens of 2.5 cm focal length along the resonator axis. Sequence of Laguerre-Gaussian (LGp,l) modes with different combinations of radial (p) and azimuthal (l) indices from low to high orders (p = 0 – 12, l = ...
Tópico(s): Advanced Fiber Laser Technologies
2010 - IOP Publishing | Laser Physics Letters
Many laser applications require specific irradiance distributions to ensure optimal performance. Geometric optical design methods based on numerical calculation of two plano-aspheric lenses have been thoroughly studied in the past. In this work, we present an alternative new design approach based on functional differential equations that allows direct calculation of the rotational symmetric lens profiles described by two-point Taylor polynomials. The formalism is used to design a Gaussian to flat- ...
Tópico(s):
2014 - Optica Publishing Group | Optics Express
Mahin Naserpour, Carlos J. Zapata–Rodríguez, Carlos Díaz-Aviñó, Mahdieh Hashemi,
We design plano-concave silicon lenses with coupled gradient-index plasmonic metacoatings for ultrawide apertured focusing utilizing a reduced region of $\sim 20 \lambda^2$. The anomalous refraction induced in the planar input side of the lens and in the boundary of the wavelength-scale focal region boosts the curvature of the emerging wavefront, thus significantly enhancing the resolution of the tightly-focused optical wave. The formation of a light tongue with dimensions approaching those of the ...
Tópico(s): Plasmonic and Surface Plasmon Research
2016 - Optica Publishing Group | Journal of the Optical Society of America B
A. Ghaffar, M. H. Shahzad, Muhammad Yasin Naz, Shakeel Ahmed, Muhammad Sharif, Qaisar Abbas Naqvi, Aqeel A. Syed,
Abstract —In this paper, the transmission of the electromagnetic waves through a plano convex lens of lossless uniaxial chiral medium is derived using dyadic transmission coefficient. Derived geometrical optics field is valid everywhere except at focal point where it gives infinite value.Singularity of the field at focal point is addressed using Maslov's method. The effects of different constitutive parameters on the refracted field are also discussed.
Tópico(s): Metamaterials and Metasurfaces Applications
2012 - Taylor & Francis | Journal of Electromagnetic Waves and Applications
Bruna Cirqueira Almeida, Cláudia da Silva Aguiar Rezende, Marcelo Mendes Pedroza, Ranyere do Nascimento Lôbo, Matheus Gomes Arruda,
... de azul de metileno em uma mesa agitadora orbital, seguindo um plano de delineamento de faces centradas com 11 diferentes ...
Tópico(s): Catalysis and Hydrodesulfurization Studies
2024 - | Revista AIDIS de Ingeniería y Ciencias Ambientales Investigación desarrollo y práctica
Yuri V. Senatsky, Jean‐François Bisson, A. V. Shelobolin, A. Shirakawa, K. Ueda,
The possibility of use of ordinary short-focus lenses with strong spherical aberration for mode selection in a laser resonator is demonstrated. Plano-convex spherical lenses with foci from 2.5 to 10.0 cm placed inside the resonator of the CW laser diode pumped Yb:YAG laser were used to select circular modes of Laguerre-Gauss and Bessel-Gauss type, or to get ring-like, multi-mode off-axis oscillations with variable inner and outer diameters of rings. At the constant pump power mode selection was ...
Tópico(s): Advanced Fiber Laser Technologies
2009 - IOP Publishing | Laser Physics
Young‐Wook Kim, Jiwon Jeong, Se Hyun Lee, Jae‐Hoon Kim, Chang‐Jae Yu,
The switching speed of a polarization-independent microlens array fabricated with a nematic liquid crystal (NLC) in the configuration of a plano-convex lens is improved by the reactive mesogen (RM) mixed in an alignment layer. Due to the NLC rotating directions predetermined by the polymerized RM, the direct switching from a vertical alignment to a spiral one is obtained without going through a metastable splay state, which gives rise to slow response in the vertically aligned NLC microlens with polarization ...
Tópico(s): Photonic Crystals and Applications
2010 - Institute of Physics | Applied Physics Express
Abstract It is shown that the use of a super-Gaussian aperture of order five to ten for fundamental mode selection in plano-concave cavity gives better results (1) than for a Gaussian aperture for its lower TEM00 mode losses and, (2) than a hard aperture for its smoothing edge effects yielding more regular TEM00 mode profiles. Explicit results are given in hard and soft aperture cases for the transverse mode discrimination and fundamental mode losses.
Tópico(s):
1993 - Taylor & Francis | Journal of Modern Optics
Yougang Ke, Shizhen Chen, Weixing Shu, Hailu Luo,
Based on the combined modulation of geometric phase introduced by a metasurface and dynamic phase created by a plano-convex lens, we propose and demonstrate a simple and convenient method to generate perfect vector beams. The metasurface converts an incident Gaussian beam with circular polarization to the higher-order Bessel–Gauss modes. The followed lens realizes the Fourier transformation and produces perfect vortex beam at the focal plane. Furthermore, by controlling the incident polarization, ...
Tópico(s): Plasmonic and Surface Plasmon Research
2019 - Elsevier BV | Optics Communications
Kamel Aı̈t-Ameur, H. Ladjouze, G. Stéphan,
Diffraction patterns and divergence of the fundamental mode of a laser are studied in the case of a plano-concave cavity with two-apertured mirrors. The effects of both apertures are shown to be nonequivalent. The sizes of their diameters control the geometry of the beam and, in particular, control the increase or the decrease of the divergence with respect to that of the nondiaphragmed cavity.
Tópico(s): Metamaterials and Metasurfaces Applications
1992 - Optica Publishing Group | Applied Optics
Xiaoqin Wu, Qiushu Chen, Yipei Wang, Xiaotian Tan, Xudong Fan,
We discover that stable high-Q bouncing ball modes with tight lateral confinement and whole-body light–matter interaction can exist in an imperfectly aligned, wedged plano–plano FP (WFP) cavity by simply introducing a vertical dielectric interface (DI) between two media with different refractive indices. Compared to a pure WFP cavity without the DI, which is known to have a low-Q factor and a finesse of 10–300 due to the large diffraction and geometrical walk-off losses, our WFP-DI cavity exhibits ...
Tópico(s): Photonic and Optical Devices
2019 - American Chemical Society | ACS Photonics
A. Hakola, Timo Hakkarainen, Rurik Tommila, T. Kajava,
We discuss the generation of Bessel–Gauss pulses directly from a diode-pumped solid-state laser. The laser resonator has a plano–concave configuration with the concave end mirror replaced with a diffractive phase element. As the active material, Nd-doped yttrium lithium fluoride (YLF) and GdVO4 crystals have been used. The pulsed operation is obtained by passively Q-switching the laser using Cr4+:yttrium aluminum garnet (YAG) crystals with different unsaturated transmission coefficients. When guiding ...
Tópico(s): Laser-Matter Interactions and Applications
2010 - Optica Publishing Group | Journal of the Optical Society of America B
Shekhar Guha, Leonel P. Gonzalez, Qin Sheng,
Abstract We describe here the propagation of light through a plano‐convex spherical lens using the Stratton‐Chu vector diffraction integrals. The values of the electric and magnetic fields on the two lens surfaces and at a point outside the lens are calculated by repeated use of the diffraction integrals and the intensity distribution in the focal region of the lens is determined. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tópico(s): Digital Holography and Microscopy
2007 - Wiley | PAMM
Produção Nacional
Revisado por pares
Salla Gangi Reddy, Ashok Kumar, Shashi Prabhakar, R. P. Singh,
We have experimentally reproduced ring shaped beams from the scattered Laguerre-Gaussian and Bessel-Gaussian beams. A rotating ground glass plate is used as a scattering medium and a plano convex lens collects the scattered light to generate ring shaped beams at the Fourier plane. The obtained experimental results are supported with the numerical results and are in good agreement with the theoretical results proposed by Wang, Cai and Korotkova (Opt. Exp. 17, 22366 (2009)).
Tópico(s): Optical Coherence Tomography Applications
2013 - Optica Publishing Group | Optics Letters
Ching-Hsu Chen, Chi-Feng Chiu,
We study both numerically and experimentally a specific geometric mode, named VW mode, in an end-pumped Nd:YVO4 laser with a plano-concave cavity near the 1/3-degeneracy. Three theoretical methods are used to analyze the transverse profiles, the operator method [J. Opt. Soc. Am. A 22, 1559 (2005)], the SU(2) wave representation [Phys. Rev. A 69, 053807 (2004)], and the Fox-Li approach. Some differences among them are addressed and clarified. Moreover, the generating conditions for VW mode are found ...
Tópico(s):
2007 - Optica Publishing Group | Optics Express
B. S. Harshith, G. K. Samanta,
Abstract We report on a simple and compact experimental scheme to generate high-power, ultrafast, higher-order vortex-array beams. Simply by using a dielectric microlens-array (MLA) and a plano-convex lens, we have generated array-beams carrying the spatial property of the input beam. Considering the MLA as a 2D sinusoidal phase-grating, we have numerically calculated the intensity pattern of the array-beams in close agreement with the experimental results. Using vortex beams of order as high as ...
Tópico(s): Plasmonic and Surface Plasmon Research
2019 - Nature Portfolio | Scientific Reports
Modes of a diaphragmed laser are expressed as linear combinations of Laguerre-Gauss functions and computed from the resonance condition. Hard and soft apertures are considered. Explicit results are given in both cases for the phase and amplitude distributions inside and outside a plano-concave cavity and for the three modes having the lowest losses. Deformations of modes with the diameter of the diaphragm are also given, showing the evolution of lateral lobes.
Tópico(s):
1991 - Optica Publishing Group | Applied Optics