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Polo, A. (author), Bociort, F. (author), Pereira, S.F. (author), Urbach, H.P. (author)Accurate wavefront aberration measurement are essential for next-generation Extreme Ultraviolet (EUV) Lithography. During the past years several accurate interferometric techniques have been developed, but these techniques have limitation. In this work we discuss a different technique based on the Hartmann Wavefront Sensor that requires no...conference paper
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Xu, M. (author), Urbach, H.P. (author), De Boer, D.K.G. (author), Cornelissen, H.J. (author)The application of wire grid polarizers as efficient polarizing beam splitters for visible light is studied. The large differences between the transmissivity for different polarizations are explained qualitatively by using the theory of metallic wave guides. The results of rigorous calculations obtained by using the finite element method are...journal article 2005
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Wei, X. (author), Urbach, H.P. (author), Wachters, A. (author), Aksenov, Y. (author)The polarization induced by the mask is studied by using a 3D rigorous model, wich solves Maxwell equations using the finite element method. Teh aerial image depends strongly on the change of polarization induced by the materials, thickness of the layer and pitch of the periodic masks.conference paper 2005
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Brok, J.M. (author), Urbach, H.P. (author)We discuss a mode expansion technique to rigorously model the diffraction from three-dimensional pits and holes in a perfectly conducting layer with finite thickness. On the basis of our simulations we predict extraordinary transmission through a single hole, caused by the Fabry-Perot effect inside the hole. Furthermore, we study the fundamental...journal article 2006
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De Boer, D.K.G. (author), Urbach, H.P. (author), Xu, M. (author)Poster presentation Optics Research Group TU Delft in cooperation with Philips and STWjournal article 2006
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Janssen, O.T.A. (author), Urbach, H.P. (author), 't Hooft, G.W. (author)The excitation of surface plasmons by subwavelength slits in metal films is studied using a rigorous diffraction model. It is shown that the plasmon is launched by a slit in antiphase with the incident magnetic field. This is true independent of slit width and of the metal used. Using this phase information, maxima and minima in transmission are...journal article 2006
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- Janssen, O.T.A. (author), Urbach, H.P. (author), 't Hooft, G.W. (author) journal article 2007
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Wei, X. (author), Wachters, A.J.H. (author), Urbach, H.P. (author)We present a three-dimensional model based on the finite-element method for solving the time harmonic Maxwell equation in optics. It applies to isotropic or anisotropic dielectrics and metals and to many configurations such as an isolated scatterer in a multilayer, bi-gratings, and crystals. We discuss the application of the model to near-field...journal article 2007
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Xu, M. (author), Urbach, H.P. (author), De Boer, D.K.G. (author)A color and polarization separating backlight can be obtained by using a surface-relief grating made of birefringent material as an outcoupling structure on top of the lightguide. A rigorous finite element diffraction model was applied to study the polarization effect of such a grating. The diffraction of plane waves by the anisotropic grating...journal article 2007
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Janssen, O.T.A. (author), Van Haver, S. (author), Janssen, A.J.E.M. (author), Braat, J.J.M. (author), Urbach, H.P. (author), Pereira, S.F. (author)Results are presented of mask imaging using the Extended Nijboer-Zernike (ENZ) theory of diffraction. We show that the efficiency of a mask imaging algorithm, derived from this theory, can be increased. By adjusting the basic Finite Difference Time Domain (FDTD) algorithm, we can calculate the near field of isolated mask structures efficiently,...conference paper 2008
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Van Haver, S. (author), Janssen, O.T.A. (author), Braat, J.J.M. (author), Janssen, A.J.E.M. (author), Urbach, H.P. (author), Pereira, S.F. (author)In this paper we introduce a new mask imaging algorithm that is based on the source point integration method (or Abbe method). The method presented here distinguishes itself from existing methods by exploiting the through-focus imaging feature of the Extended Nijboer-Zernike (ENZ) theory of diffraction. An introduction to ENZ-theory and its...conference paper 2008
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Urbach, H.P. (author), Pereira, S.F. (author)Closed formulas are presented for the field in the lens pupil for which the longitudinal electric component at the focal point is larger than any other focused field with the same power. The fullwidth-at-half-maximum of the squared amplitude of the maximum longitudinal component is 15% to 30% less than that of the classical Airy spot.journal article 2008
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Cui, M. (author), Bhattacharya, N. (author), Urbach, H.P. (author), Van den berg, S.A. (author)We experimentally demonstrate that a stabilized femtosecond frequency comb can be applied as a tool for distance measurement. The scheme is based on optical interference between individual pulses in a Michelson type interferometer. The cross-correlation functions between individual pulses with a distance of around 15 meter and 30 meter are...conference paper 2008
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Zeitouny, M. (author), Bhattacharya, N. (author), Urbach, H.P. (author), Van den Berg, S.A. (author)Frequency and distance metrology have been revolutionized with the arrival of stabilized frequency comb lasers. We discuss several aspects of distance metrology specially the contribution of the dispersion in by air.conference paper 2008
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Xu, M. (author), De Sio, L. (author), Caputo, R. (author), Umeton, C.P. (author), Wachters, A.J.H. (author), De Boer, D.K.G. (author), Urbach, H.P. (author)Recently, a novel holographic diffraction grating made of polymer slices alternated to homogeneous films of nematic liquid crystal (POLICRYPS) was realized. We study the optical performance of the POLICRYPS gratings by both numerical simulations and experiments. Characterization of the grating at normal and conical reading mount are performed....journal article 2008
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Sluijter, M. (author), De Boer, D.K.G. (author), Urbach, H.P. (author)We present simulations of a novel liquid-crystal-based electro-optical device that enables a switching effect owing to a backreflection phenomenon. In the simulations, we exploit the optical properties of a liquid-crystal layer with a Freédericksz alignment in an unconventional way. The resulting switching effect of the proposed optical design...journal article 2008
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- Sluijter, M. (author), De Boer, D.K.G. (author), Urbach, H.P. (author), Strömer, J. (author), Cennini, G. (author) conference paper 2009
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Sluijter, M. (author), De Boer, D.K.G. (author), Urbach, H.P. (author)Firm evidence of the biaxial nematic phase in liquid crystals, not induced by a magnetic or electric field, has been established only recently. The discovery of these biaxially anisotropic liquid crystals has opened up new areas of both fundamental and applied research. The advances in biaxial liquid crystal-related topics call for a good...journal article 2009
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Urbach, H.P. (author), Pereira, S.F. (author)Closed formulas are derived for the field in the focal region of a diffraction limited lens, such that the electric field component in a given direction at the focal point is larger than that of all other focused fields with the same power in the entrance pupil of the lens. Furthermore, closed formulas are derived for the corresponding optimum...journal article 2009
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Cui, M. (author), Zeitouny, M.G. (author), Bhattacharya, N. (author), Van den Berg, S.A. (author), Urbach, H.P. (author), Braat, J.J.M. (author)We experimentally demonstrate that a femtosecond frequency comb laser can be applied as a tool for longdistance measurement in air. Our method is based on the measurement of cross correlation between individual pulses in a Michelson interferometer. From the position of the correlation functions, distances of up to 50 m have been measured. We...journal article 2009