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Krieg, M.L. (author), Braat, J.J.M. (author)A previously reported interferometer without intermediate optics is used to perform measurements on an aspherical extreme ultraviolet lithography mirror substrate. Acousto-optic modulation based phase shifting is used together with a novel phase retrieval algorithm to retrieve the phase distribution from our interferograms. The phase...conference paper 2005
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- Dirksen, P. (author), Braat, J.J.M. (author), Janssen, A.J.E.M. (author), Leeuwesteijn, A. (author) conference paper 2005
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Koek, W.D. (author), Chan, V.S.S. (author), Ooms, T.A. (author), Bhattacharya, N. (author), Westerweel, J. (author), Braat, J.J.M. (author)We present a novel holographic particle image velocimetry (HPIV) system using a reversible holographic material as the recording medium. In HPIV the three-dimensional flow field throughout a volume is detected by adding small tracer particles to a normally transparent medium. By recording the particle distribution twice with a known time shift...conference paper 2005
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Koek, W.D. (author), Bhattacharya, N. (author), Braat, J.J.M. (author), Ooms, T.A. (author), Westerweel, J. (author)A theoretical analysis describing the dependence of the signal-tonoise ratio (SNR) on the number of pixels and the number of particles is presented for in-line digital particle holography. The validity of the theory is verified by means of numerical simulation. Based on the theory we present a practical performance benchmark for digital...journal article 2005
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Braat, J.J.M. (author), Nugrowati, A.M. (author), Van de Nes, A.S. (author), Pereira, S.F. (author)Poster presentation Optics Research Group TU Delftjournal article 2005
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Marinescu, O.E. (author), Bociort, F. (author), Braat, J.J.M. (author)Poster presentation Optics Research Group TU Delft in cooperation with ASM Lithograpy and TNOjournal article 2005
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Braat, J.J.M. (author), Marinescu, O.E. (author), Bociort, F. (author)Poster presentation Optics Research Group TU Delft in cooperation with ASM Lithograpy and TNOjournal article 2005
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Montilla, I. (author), Pereira, S.F. (author), Braat, J.J.M. (author)A new interferometric technique for Michelson wide-field interferometry is presented that consists of a Michelson pupil-plane combination scheme in which a wide field of view can be achieved in one shot. This technique uses a stair-shaped mirror in the intermediate image plane of each telescope in the array, allowing for simultaneous correction...journal article 2005
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- Bal, M.F. (author), Singh, M. (author), Braat, J.J.M. (author) journal article 2004
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Montilla, I. (author), Pereira, S.F. (author), Braat, J.J.M. (author)Wide field interferometry has become a subject of increasing interest in the recent years. New methods have been suggested in order to avoid the drawbacks of the standard wide field method (homothetic mapping) which is not applicable when the aperture is highly diluted; for this reason imaging with non-homothetic arrays is being extensively...conference paper 2004
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Braat, J.J.M. (author), Dirksen, P. (author), Janssen, A.J.E.M. (author), Van de Nes, A.S. (author)Poster presentation with Philips Research Laboratoriesjournal article 2004
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Swinkels, B.L. (author), Wendrich, T.J. (author), Bhattacharya, N. (author), Wielders, A.A. (author), Braat, J.J.M. (author)Space interferometers consisting of several free flying telescopes, such as the planned Darwin mission, require a complex metrology system to make all the components operate as a single instrument. Our research focuses on one of its sub-systems that measures the absolute distance between two satellites with high accuracy. For Darwin the required...conference paper 2004
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Wang, H. (author), Groen, F.H. (author), Pereira, S.F. (author), Braat, J.J.M. (author)We present an analysis of the reading capability of a novel optical pickup consisting of a single-mode and a multi-mode rectangular waveguide. According to the simulations, if one has prior information about the structure of the disk, superresolution readout could be achieved. The proposed system has the advantage to be compact and should be...conference paper 2004
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Musa, S. (author), Pereira, S.F. (author), Braat, J.J.M. (author), Fransoo, F. (author), Van Thourhout, D. (author), Baets, R. (author)We present a study on the use of optical waveguides in readout units for optical recording. Optical waveguides can be used to increase the storage capacity of optical recording, which is limited by diffraction. Optical waveguides are attractive for application in readout units of optical recording systems because it is possible to make compact...conference paper 2004
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Voogd, R.J. (author), Singh, M. (author), Braat, J.J.M. (author)We present a method to optically store multiple information in one location by having angular momentum imparted to the scanning beam by optical phase objects that make up the information areas on a surface. We show that the light beam thus perturbed carries an optical vortex, the rotation of which can be detected in the near-field focal region...conference paper 2004
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Krieg, M.L. (author), Braat, J.J.M. (author)This paper will illustrate several approaches to retrieving the shape of aspherical reflective surfaces as used in EUV Lithography, from measurements from a previously reported angstrom-accuracy interferometer. First, the working principles of the interferometer will be reviewed, and typical measurement data expected from the instrument will be...conference paper 2004
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Braat, J.J.M. (author), Bociort, F. (author), Marinescu, O.E. (author)Poster presentation Optics Research Group TU Delft in cooperation with ASM Lithograpyjournal article 2004
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Braat, J.J.M. (author), Marinescu, O.E. (author), Bociort, F. (author)Poster presentation Optics Research Group TU Delft in cooperation with ASM Lithograpyjournal article 2004
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Booij, S.M. (author), Fähnle, O.W. (author), Meeder, M. (author), Wons, T. (author), Braat, J.J.M. (author)A variation on the fluid jet polishing (FJP) technique, arbitrarily named Jules Verne (JV), will be described in this article. Jules Verne is a glass processing technique that removes material due to the fact that the tool and the surface are in close contact, and a slurry moves in between the tool and the surface. This approach has both...conference paper 2003
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Wang, H. (author), Groen, F.H. (author), Pereira, S.F. (author), Braat, J.J.M. (author)In photonics, light usually diffracts in all directions when it emerges from a planar optical waveguide. Besides this fact, in this letter we show that a waveguide with a rectangular cross section can be turned to a focusing system by using three-dimensional self-imaging technique. We obtained a configuration where the focus of the field lies...journal article 2003