Imperial College London

ProfessorPeterTörök

Faculty of Natural SciencesDepartment of Physics

Visiting Professor
 
 
 
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Contact

 

+44 (0)20 7594 7753peter.torok Website

 
 
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Location

 

609Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

131 results found

Romero CAM, Van de Nes AS, Foreman MR, Munro P, Toeroek Pet al., 2010, Multiplexed optical data storage and vectorial ray tracing, 1st NanoCharM Workshop on Advanced Polarimetric Instrumentation (API), Publisher: E D P SCIENCES, ISSN: 2100-014X

Conference paper

Foreman MR, Torok P, 2010, Computational methods in vectorial imaging, Journal of Modern Optics, ISSN: 0950-0340

Journal article

Foreman MR, Torok P, 2009, Focusing of spatially inhomogeneous partially coherent, partially polarized electromagnetic fields, J OPT SOC AM A, Vol: 26, Pages: 2470-2479, ISSN: 1084-7529

We report a general framework capable of describing the focusing of electromagnetic waves with spatially varying coherence and polarization properties in optical systems of arbitrary numerical aperture and Fresnel number. We also investigate the reduction of the dimensionality of the requisite integrals by use of a coherent mode expansion. We find that coherent mode expansions treating each component of the electric field vector individually are unsuitable for describing focusing systems because of the inter-component mixing that can occur in high numerical aperture systems. In addition, we show that the assumption of harmonic angular dependence allows the azimuthal integration to be performed analytically, providing further simplification of the analysis. We also find that the effective degree of spectral coherence of an electromagnetic beam is unchanged upon focusing. Finally, as an illustration of the developed framework, we calculate the transverse and axial focal distributions for a partially coherent source formed by incoherent superposition of radially and azimuthally polarized Laguerre-Gauss modes. (C) 2009 Optical Society of America

Journal article

Foreman MR, Toeroek P, 2009, Singular system analysis in electromagnetic focusing problems, 2nd International Workshop on Theoretical and Computational Nanophotonics (TaCoNa-Photonics 2009), Publisher: AMER INST PHYSICS, Pages: 13-13, ISSN: 0094-243X

Conference paper

Munro PRT, Toeroek P, 2008, Properties of high-numerical-aperture Mueller-matrix polarimeters, OPTICS LETTERS, Vol: 33, Pages: 2428-2430, ISSN: 0146-9592

Journal article

Foreman MR, Macias Romero C, Török P, 2008, A priori information and optimisation in polarimetry., Opt Express, Vol: 16, Pages: 15212-15227

Polarimetric measurements are designed to obtain information pertaining to the system under study, however noise in the system limits the precision and hence information obtainable. Exploitation of a priori knowledge of the system allows for an improvement in the precision of experimental data. In this vein we present a framework for system design and optimisation based upon the Fisher information matrix, which allows easy incorporation of such a priori information. As such the proposed figure of merit is more complete than the commonly used condition number. Conditions of equivalence are considered, however a number of examples highlight the failings of the condition number under more general scenarios. Bounds on the achievable informational gains via multiple polarimeter arms are also given. Finally we present analytic results concerning error distribution in a Mueller matrix polar decomposition, allowing for a more accurate noise analysis in polarimetric experiments.

Journal article

Foreman MR, Romero CM, Toeroek P, 2008, <i>A priori</i> information and optimisation in polarimetry, OPTICS EXPRESS, Vol: 16, Pages: 15212-15227, ISSN: 1094-4087

Journal article

Foreman MR, Romero CM, Török P, 2008, Determination of the three-dimensional orientation of single molecules., Opt Lett, Vol: 33, Pages: 1020-1022, ISSN: 0146-9592

A simple method for real-time determination of the full three-dimensional orientation of the emission dipole of single molecules is presented. Introduction of a pi phase step in the back focal plane of the collector lens breaks the inherent symmetry, allowing the longitudinal dipole component to be measured. Experimental tolerances and the consequence of a nonzero bandwidth emission spectrum are also discussed. The scheme also allows for the longitudinal component of an electric field to be found experimentally.

Journal article

Torok P, Munro PRT, Kriezis EE, 2008, High numerical aperture vectorial imaging in coherent optical microscopes, OPTICS EXPRESS, Vol: 16, Pages: 507-523, ISSN: 1094-4087

Journal article

Foreman MR, Macías Romero C, Török P, 2008, Determination of the three dimensional orientation of single molecules, Opt. Lett., Vol: 33, Pages: 1020-1022

Journal article

Foreman MR, Sherif SS, Munro PRT, Török Pet al., 2008, Inversion of the Debye-Wolf diffraction integral using an eigenfunction representation of the electric fields in the focal region, Opt. Express, Vol: 16, Pages: 4901-4917

Journal article

Sherif SS, Foreman MR, Török P, 2008, Eigenfunction expansion of the electric fields in the focal region of a high numerical aperture focusing system, Opt. Express, Vol: 16, Pages: 3397-3407

Journal article

van de Nes, Török P, 2007, Rigorous analysis of spheres in Gauss-Laguerre beams, Opt. Express, Vol: 15, Pages: 13360-13374

Journal article

Munro PRT, Török P, 2007, Calculation of the image of an arbitrary vectorial electromagnetic field, Optics Express, Vol: 15, Pages: 9293-9307, ISSN: 1094-4087

In order to rigorously calculate the image of a scattered field, it must be propagated into the far-field before vectorial focusing theory is applied. This approach may become difficult when, for example, the scattering object is embedded in a stratified medium, requiring calculation of the appropriate Green’s tensor. We present a method for calculating the image of an arbitrary vectorial field by decomposing the field into a superposition of magnetic-dipole waves. We show that this technique can significantly simplify the calculation of the image of arbitrary vectorial fields even when the field is known within a stratified medium. The technique is more computationally efficient than existing methods however we also show that the method retains accuracy.

Journal article

Foreman MR, Sherif SS, Török P, 2007, Photon statistics in single molecule orientational imaging, Opt. Express, Vol: 15, Pages: 13597-13606

Journal article

Török P, Munro PRT, Kriezis EE, 2006, Rigorous near- to far-field transformation for vectorial diffraction calculations and its numerical implementation, JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION, Vol: 23, Pages: 713-722, ISSN: 1084-7529

Journal article

Braat J, Bertolotti M, Toeroek P, 2006, Welcome to a new electronic journal, JOURNAL OF THE EUROPEAN OPTICAL SOCIETY-RAPID PUBLICATIONS, Vol: 1, ISSN: 1990-2573

Journal article

Torok P, Salt M, Munro P, Kriezis E, Herzig HP, Rockstuhl Cet al., 2006, Multiplexed optical data storage, Topical Meeting on Optical Data Storage, Publisher: IEEE, Pages: 182-+

Conference paper

Munro PRT, Török P, 2005, Vectorial, high numerical aperture study of Nomarski's differential interference contrast microscope, OPTICS EXPRESS, Vol: 13, Pages: 6833-6847, ISSN: 1094-4087

Journal article

Sherif SS, Török P, 2005, Eigenfunction representation of the integrals of the Debye-Wolf diffraction formula, JOURNAL OF MODERN OPTICS, Vol: 52, Pages: 857-876, ISSN: 0950-0340

Journal article

Trk P, 2005, Superresolution in classical optics, EUROPHOTON 2004, Cargese, Corsica, France, 6 - 11 September 2004

Conference paper

Trk P, 2005, Vectorial focusing and imaging, SPIE 48th annual symposium on optical science and technology, San Diego, California USA, 3 8 August 2003

Conference paper

Sherif SS, Török P, 2004, Pupil plane masks for super-resolution in high-numerical-aperture focusing, JOURNAL OF MODERN OPTICS, Vol: 51, Pages: 2007-2019, ISSN: 0950-0340

Journal article

Munro PRT, Török P, 2004, Vectorial, high-numerical-aperture study of phase-contrast microscopes, JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION, Vol: 21, Pages: 1714-1723, ISSN: 1084-7529

Journal article

Munro PRT, Török P, 2004, Vectorial, high-numerical-aperture study of phase-contrast microscopes., J Opt Soc Am A Opt Image Sci Vis, Vol: 21, Pages: 1714-1723, ISSN: 1084-7529

We describe, using a high-numerical-aperture vectorial model, the image formation of phase-contrast microscopes. In particular, imaging of a weak phase object is considered. We show that, partly owing to the fact that phase-contrast microscopes are interference microscopes, their image formation is fundamentally different from that of conventional transmission optical microscopes. Our detailed analysis reveals a number of yet undocumented properties of these microscopes, including that depending on the given configuration, they can exhibit an improved lateral resolution when larger detectors are used in comparison with that obtained for a small detector size. We present numerical examples to explain this phenomenon and discuss our analysis in detail.

Journal article

Török P, Munro PRT, 2004, The use of Gauss-Laguerre vector beams in STED microscopy, OPTICS EXPRESS, Vol: 12, Pages: 3605-3617, ISSN: 1094-4087

Journal article

Munro PRT, Török P, 2004, Effect of detector size on optical resolution in phase contrast microscopes, OPTICS LETTERS, Vol: 29, Pages: 623-625, ISSN: 0146-9592

Journal article

Munro PRT, Török P, 2004, Effect of detector size on optical resolution in phase contrast microscopes., Opt Lett, Vol: 29, Pages: 623-625, ISSN: 0146-9592

We examine the effects of detector size on the imaging properties of a scanning phase contrast microscope. The lateral size of the point-spread function is found to be wider when a point detector is used than when a much larger detector is used. Combining this finding with the well-known difficulties involved in using a confocal microscope in transmission mode suggests that a phase contrast microscope employing a point detector will in general have inferior imaging properties compared with one employing a large detector.

Journal article

van de Nes AS, Munro PRT, Pereira SF, Braat JJM, Török Pet al., 2004, Cylindrical vector beam focusing through a dielectric interface:: comment, OPTICS EXPRESS, Vol: 12, Pages: 967-969, ISSN: 1094-4087

Journal article

Trk P, 2004, Superresolution in linear optical imaging by classical means (Oral presentation), EuroPhoton 2004

Conference paper

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