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Derkink, F.M. (author), Doelman, D. (author), van Dam, D. (author), Brenny, B.J.M. (author), Speet, B.G. (author), van Brug, H. (author), Keller, C. (author), Snik, F. (author)While the concentrations of trace gases in Earth’s atmosphere were roughly constant for thousands of years, human activities such as the burning of fossil fuels have caused significant changes ever since the industrial revolution. The remote sensing of trace gases has proved to be a useful technique for mapping and monitoring on the global scale...conference paper 2022
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van Brug, H. (author), Visser, H. (author), Brenny, B.J.M. (author), van der Valk, N.C.J. (author), Sierk, B. (author), Heliere, A. (author), Rusli, S. (author), Landgraf, J. (author)CarbonHIGS is a 2D imager designed to measure the enhancement of CO2 concentration in emission plumes from power plants. The origin of HIGS, and the physics of the working principle will be explained. Two possible implementations of HIGS will be presented, i.e. one that uses power splitting while the other one uses polarization splitting. The...conference paper 2020
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Brouwer, E.A.M. (author), van Buuren, R.A. (author), Gawlitta, N. (author), Grabarnik, S. (author), van der Valk, N.C.J. (author), Vink, H.J.P. (author), van Brug, H. (author), Visser, H. (author)Earth observation measurements at wavelengths below 320nm are challenging due to the steep decrease of the earth irradiance towards shorter wavelengths. Stray light and ghosting of longer wave light can easily overwhelm the signals at short wavelengths. In the UV channel (270-320nm) of the TROPOMI instrument this challenge has been addressed...conference paper 2017
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van Brug, H. (author), Visser, H. (author)This paper describes one of the issues that are facing the remote sensing community in the not so far future; scientists ask for certain requirement that cannot be fulfilled either due to cost issues or technological issues. The paper starts with giving a short and quick historical overview of the development of spectrometer based remote sensing...conference paper 2016
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Gür, B. (author), van Brug, H. (author), Xu, M. (author), Vela Esparza, E. (author)The "Bi-Directional Scattering Function" BSDF of a diffuser depends on several parameters, such as surface properties, observational conditions and further. This paper describes experimental activities to achieve a better understanding about the interaction between diffuser properties and performance with regards to its scattering behavior. For...conference paper 2014
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Gür, B. (author), van Brug, H. (author), Xu, M. (author), Vela Esparza, E. (author)The "Bi-Directional Scattering Function" BSDF of a diffuser depends on several parameters, such as surface properties, observational conditions and further. This paper describes experimental activities to achieve a better understanding about the interaction between diffuser properties and performance with regards to its scattering behavior. For...conference paper 2014
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Agócs, T. (author), Navarro, R. (author), Venema, L. (author), van Amerongen, A.H. (author), Tol, P.J.J. (author), van Brug, H. (author), Brandl, B.R. (author), Molster, F. (author), Todd, S. (author)We present innovative, immersed grating based optical designs for the SMO (Spectrograph Main Optics) module of the Mid-infrared E-ELT Imager and Spectrograph, METIS. The immersed grating allows a significant reduction of SMO volume compared to conventional echelle grating designs, because the diffraction takes place in high refractive index...conference paper 2014
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Verlaan, A.L. (author), van Brug, H. (author), Visser, H. (author)A novel design for a earth observation combined spectrometer and polarimeter is presented. The goal of the instrument is to measure both intensity (radiance) and the state of polarization. Some backgrounds for this instrument are presented but the main part of this article will be on the optical design and the ideas behind it. © 2013 SPIE.conference paper 2013
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van Brug, H. (author), Scalia, P.S. (author)The origin of spectral features, speckle effects, is explained, followed by a discussion on many aspects of spectral features generation. The next part gives an overview of means to limit the amplitude of the spectral features. This paper gives a discussion of all means to reduce the spectral features amplitude (SFA), i.e. inner pixel averaging,...conference paper 2012
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van Amerongen, A.H. (author), Agocs, T. (author), van Brug, H. (author), Nieuwland, G. (author), Venema, L. (author), Hoogeveen, R.W.M. (author)We have developed the technology to manufacture an immersed grating in silicon for the Mid-infrared E-ELT Imager and Spectrograph, METIS. We show that we can meet the required diffraction-limited performance at a resolution of 100000 for the L and M spectral bands. Compared to a conventional grating, the immersed grating drastically reduces the...conference paper 2012
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van Brug, H. (author)This article will give an overview of all effects that determine the spectral features amplitude (SFA). The origin of spectral features is explained and methods are indicated that can be used to minimize the SFA. Spectral features are observed in the ratio between two spectra of sun calibration measurements. Mechanisms helping to reduce spectral...conference paper 2011
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TNO Industrie en Techniek (author), Nijkerk, M.D. (author), Koster, N.B. (author), van Brug, H. (author), Maas, D.J. (author)A method for actinic inspection of EUV mask blanks is described, in which EUV photoresist is applied to the blank, flood exposed with EUV, and developed. The effect of both phase and reflectivity defects on the reticle is described in terms of a variation in intensity and phase of the standing wave in the resist. Thin film simulations are...conference paper 2010
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TNO Industrie en Techniek (author), van Brug, H. (author), ten Bloemendal, D. (author), de Goeij, B. (author), Vink, R. (author), Maresi, L. (author)Spectral features are introduced by the diffuser that is used during on-board sun calibration. New findings are presented on how to reduce the size of these spectral features. Reduction can be obtained via optical design of the calibration unit, but also in creating a better diffuser. A novel diffuser design will be presented and its performance...conference paper 2009
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- Otter, G.C.J. (author), Bazalgette Courrèges-Lacoste, G. (author), van Brug, H. (author), Groote Schaarsberg, J.J.M. (author), Delwart, S. (author), del Bello, U. (author), TNO Industrie en Techniek (author) conference paper 2006
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TNO Industrie en Techniek (author), van Brug, H. (author), Bazalgette Courrèges-Lacoste, G.A.F. (author), Otter, G.C.J. (author), Groote Schaarsberg, J.J.M. (author), Delwart, S. (author), Del Bello, U. (author)This paper reports the activities performed in the framework of the ESA contract 18432/04/NL/AR: Enhancement of diffusers BSDF Accuracy. This study was conducted to investigate properties of various diffusers. Diffusers are widely used in space instruments as part of the on-board absolute calibration. Knowledge of the behavior of the diffuser is...conference paper 2006
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TNO Industrie en Techniek (author), van Veggel, M. (author), Wielders, A.A. (author), van Brug, H. (author), Rosielle, P.C.J.N. (author), Nijmeijer, H. (author)The GAI A satellite will make a 3-D map of our Galaxy with measurement accuracy of 10 microarcseconds using two astrometric telescopes. The angle between the lines-of-sight of the two telescopes will be monitored using the Basic Angle Monitoring system with 1 microarcsecond accuracy. This system will be an interferometer consisting of a number...conference paper 2005
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Technisch Physische Dienst TNO - TH (author), van Brug, H. (author), Oostdijck, B. (author), van den Dool, T.C. (author), Giesen, P. (author), Gielesen, W.L.M. (author)The Delft Testbed Interferometer (DTI) will be presented. The basics of homothetic mapping will be explained together with the method of fulfilling the requirements as chosen in the DTI setup. The optical layout incorporates a novel tracking concept enabling the use of homothetic mapping in real telescope systems for observations on the sky. The...conference paper 2004
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Technisch Physische Dienst TNO - TH (author), Giesen, P.T.M. (author), Ouwerkerk, B.R. (author), van Brug, H. (author), van den Dool, T.C. (author), van der Avoort, C. (author)Homothetic mapping is a technique that combines the images from several telescopes so that it looks like as though they came form a single large telescope. This technique enables a much wider interferometric field of image than current techniques can provide. To investigate the feasibility, a research testbed is build know as Delft Testbed...conference paper 2004
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van der Avoort, C. (author), van Brug, H. (author), den Herder, J.W. (author), D'Arcio, L. (author), le Poole, R. (author), Braat, J. (author)Homothetic mapping is an aperture synthesis technique that allows interferometric imaging over a wide field-of-view. A laboratory experiment was set up to demonstrate the feasibility of this technique. Here, we present the first static experiments on homothetic mapping that have been done on the Delft Testbed for Interferometry (DTI). Before a...conference paper 2004
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Technisch Physische Dienst TNO - TH (author), van Brug, H. (author), Groeneveld, M. (author), Booij, S.M. (author), Braat, J.J.M. (author)A prototype of a system for in-process monitoring of material removal in fluid jet polishing (FJP) is presented. The measurements make use of temporal phase unwrapping (TPU) allowing for a large working range. The measurement system will be discussed, with all problems that had to be overcome like water on the surface and vibrations, as well as...conference paper 2002
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