Dr. Aaldert H. van Amerongen Profile

Dr. Aaldert H. van Amerongen

Manager Optical and X-ray instrumentation at SRON Netherlands Institute for Space Research

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Author

Publications (19)

Proceedings Article | 20 November 2024 Presentation + Paper

Presentation + Paper

Calibration campaign of SPEXone Second Generation: early results and instrument performance

Matej Arko, Jochen Campo, Marijn Siemons, Robbert Winkelman, Alexander Eigenraam, Paul Tol, Mario Vretenar, Jeroen Rietjens, Martijn Smit, Jos Dingjan, Raj Nalla, Jeroen Peters, Berit Ahlers, Jens Loehring, Ralf Kohlhaas, Bastiaan van Diedenhoven, Ruud Hoogeveen, Aaldert van Amerongen

Proceedings Volume 13192, 131920Q (2024) https://doi.org/10.1117/12.3031658

KEYWORDS: Calibration, Equipment, Polarization, Spectroscopy, Sensors, Polarimetry, Spectral resolution, Modulation, Tolerancing

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Proceedings Article | 19 October 2023 Presentation + Paper

Presentation + Paper

Detector characterization and upcoming instrument calibration of an improved version of the five-angle spectro-polarimeter SPEXone

Jochen Campo, Marijn Siemons, Matej Arko, Paul Tol, Jeroen Rietjens, Laura van der Schaaf, Martijn Smit, Mario Vretenar, Alexander Eigenraam, Joris van der Vlugt, Jelle Talsma, Simon Rosman, Robbert Winkelman, Jos Dingjan, Jeroen Peters, Jens Loehring, Ralf Kohlhaas, Aaldert van Amerongen, Bastiaan van Diedenhoven, Ruud Hoogeveen

Proceedings Volume 12729, 127290W (2023) https://doi.org/10.1117/12.2684431

KEYWORDS: Light sources and illumination, Calibration, Aerosols, Spectroscopy, Signal detection, Modulation, Stray light

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Proceedings Article | 12 July 2023 Open Access

Open Access

Paper

SPEXone, the multi-angle spectropolarimeter for PACE, adjusted and improved for new space applications

Ruud Hoogeveen, Ralf Kohlhaas, Jochen Campo, Jeroen Rietjens, Alexander Eigenraam, Ian Veenendaal, Marijn Siemons, Joris van der Vlugt, Jelle Talsma, Jos Dingjan, Guus Borst, Raj Nalla, Jeroen Peters, Aaldert van Amerongen, Jochen Landgraf

Proceedings Volume 12777, 127774G (2023) https://doi.org/10.1117/12.2690835

KEYWORDS: Equipment, Telescopes, Aerosols, Polarization, Mirrors, Stray light, Reflection, Tunable filters, Spectroscopy, Linear filtering

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Proceedings Article | 11 June 2021 Open Access

Open Access

Presentation + Paper

Polarimetric calibration of a spectro-polarimeter for remote sensing and characterization of aerosols

Martijn Smit, Jeroen Rietjens, Jochen Campo, Joost aan de Brugh, Aaldert van Amerongen, Otto Hasekamp, Jochen Landgraf, Xin Liu

Proceedings Volume 11852, 1185232 (2021) https://doi.org/10.1117/12.2599475

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High accuracy multi-angle polarimetry is of crucial importance for remote sensing of aerosol properties with accuracies demanded by climate and air quality studies. In this contribution, we discuss the polarimetric calibration of the multi-angle polarimeter "SPEX airborne". SPEX airborne is a multi-angle viewing instrument providing snapshot measurements of spectral radiance and degree of linear polarization at fixed viewing angles. Radiance and polarization are measured as a continuous function of wavelength in the 400-760nm range, at nine viewing angles equally distributed over an angular range of -56° to +56°. Each viewing-angle aperture has a swath of 7° with an instantaneous field of view of 0.5°l° (cross- times along-track). SPEX airborne measures the degree and angle of linear polarization of scattered sunlight by means of spectral modulation. For each field of view, the instrument records two modulated spectra. Ideally, these are perfectly in anti-phase, such that the sum of the modulated spectra is modulation free and gives the spectral radiance. The state of linear polarization is derived from the scaled difference of the modulated spectra. As a result of finite image quality at the focal plane, any spectropolarimeter using spectral modulation will show different polarimetric responses for the two modulated spectra, which breaks the anti-phase symmetry. For SPEX airborne this is indeed the case, and special care is taken both in the calibration and in the data processing. Ignoring this can lead to errors both in polarimetric and radiometric measurements. It is shown however that these errors are quite small. In this contribution, we will outline the spectral modulation technique employed by SPEX airborne to measure the state of linear polarization, explain which instrumental parameters are to be determined by calibration and how they feature in the data processing chain. We discuss the polarization calibration setup and how polarization calibration measurements are processed into useful calibration data. Taking a Mueller matrix approach, we show how differences in polarimetric responses can be mitigated, while also other imperfections like telescope polarization are accounted for without extra calibration effort. We also present a scheme to correct for sharp features in the solar spectrum, which would otherwise mix into the modulation spectra via the finite slit-width of the spectrometer and result in polarimetric errors. The effect of telescope polarization is also discussed Polarimetric calibration of SPEX airborne is relevant for SPEXone, a compact multi-angle polarimeter that builds on SPEX airborne heritage and space-borne spectrometer heritage within the Netherlands. SPEXone has been developed for NASA's PACE mission, which has a planned launch date in 2023.

Proceedings Article | 11 June 2021 Open Access

Open Access

Presentation + Paper

Optical and system performance of SPEXone, a multi-angle channeled spectropolarimeter for the NASA PACE mission

Jeroen H. Rietjens, Jochen Campo, Martijn Smit, Robbert Winkelman, Raj Nalla, Jochen Landgraf, Otto Hasekamp, Marc Oort, Aaldert van Amerongen

Proceedings Volume 11852, 1185234 (2021) https://doi.org/10.1117/12.2599531

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SPEXone is a multi-angle channeled spectropolarimeter that is developed by a Dutch consortium consisting of SRON and Airbus Defence and Space Netherlands with support from TNO. SPEXone will fly together with the Ocean Color Instrument (OCI) and the Hyper-Angular Rainbow Polarimeter-2 (HARP-2) on the NASA Plankton, Aerosol, Clouds and ocean Ecosystem (PACE) mission, which has a notional launch in 2023. SPEXone will deliver high quality hyperspectral multi-angle radiance and polarization products that, together with products from OCI and HARP2, enable unprecedented aerosol and cloud characterization from space. SPEXone employs dual beam spectral polarization modulation, in which the state of linear polarization is encoded in a spectrum as a periodic variation of the intensity. This technique enables high polarimetric accuracies in operational environments, since it provides snapshot acquisition of both radiance and polarization without moving parts. SPEXone has five viewing angles that are realized using a novel three-mirror segmented telescope assembly. The telescope focuses light captured by the five viewing angles onto a single image plane consisting of five stacked sub-slits. This multi-slit forms the entrance slit of a reflective grating spectrometer that consists of freeform mirrors and an order-sorting filter close to the focal plane, yielding an intrinsic spectral resolution of 2 nm and 5.4 km spatial resolution across the 100 km swath. The spectrometer re-images two spectral images per viewing angle following a dual beam spectral polarization modulation implementation. In this contribution, the optical performance of the telescope and spectrometer will be presented by means of star stimulus measurements at the slit plane and at the spectrometer focal plane. Measurements of the optical spot quality and preliminary measurements of stray light are compared with the optical design and with stray light simulations. We find that the measured optical performance of the telescope and spectrometer is better than modelled, showing higher resolution and lower slit keystone, thereby meeting all spatial and spectral resolution requirements. Also, preliminary stray light results indicate a higher diffuse but lower ghost contribution to the total stray light, which is in general beneficial for implementing stray light correction, which will enhance the polarimetric accuracy in inhomogeneous scenes.

Proceedings Article | 11 June 2021 Open Access

Open Access

Presentation + Paper

Characterization and video chain development of the CMOS detector applied in the multi-angle spectro-polarimeter SPEXone

Jochen Campo, Paul Tol, Joris van der Vlugt, Martijn Smit, Jelle Talsma, Jens Johansen, Alexander Eigenraam, Richard van Hees, Otto Hasekamp, Marc Oort, Aaldert van Amerongen, Jeroen Rietjens

Proceedings Volume 11852, 1185213 (2021) https://doi.org/10.1117/12.2599224

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Proceedings Article | 6 September 2019 Paper

Paper

Expected performance and error analysis for SPEXone, a multi-angle channeled spectropolarimeter for the NASA PACE mission

Jeroen Rietjens, Jochen Campo, Anantha Chanumolu, Martijn Smit, Raj Nalla, Cristina Fernandez, Jos Dingjan, Aaldert van Amerongen, Otto Hasekamp

Proceedings Volume 11132, 1113208 (2019) https://doi.org/10.1117/12.2530729

KEYWORDS: Polarimetry, Error analysis, Polarization, Modulation, Aerosols, Environmental sensing, Atmospheric corrections, Atmospheric particles, Aerospace engineering, Space operations

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SPEXone is a compact five–angle spectropolarimeter that is being developed as a contributed payload for the NASA Plankton, Aerosol, Cloud and ocean Ecosystem (PACE) observatory, to be launched in 2022. SPEXone will provide accurate atmospheric aerosol characterization from space for climate research, as well as for light path correction in support of the main Ocean Color Instrument. SPEXone employs dual beam spectral polarization modulation, in which the state of linear polarization is encoded in a spectrum as a periodic variation of the intensity. This technique enables high polarimetric accuracies in operational environments, since it provides snapshot acquisition of both radiance and polarization without moving parts. This paper presents the polarimetric error analysis and budget for SPEXone in terms of polarimetric precision and polarimetric accuracy. We consider factors that contribute to instrumental polarization and modulation efficiency, which will be calibrated on-ground with high, but finite accuracy. The sensitivity to dynamic systematic effects in a space environment, such as degradation and ageing of components and small variations in the temperature and thermal gradients is addressed and quantified. Finally, the impact of scene dependent error sources, mainly resulting from stray light, are assessed and the total polarimetric error budget is presented. We show that SPEXone complies with the radiometric SNR requirement of 300, yielding a minimum polarimetric precision of 200 (fully polarized light) to 300 (unpolarized light) over the full spectral range for dark ocean scenes at high solar zenith angle. Assuming a stray light correction factor of 5 and considering a moderate contrast scene, the expected in-flight polarimetric accuracy of SPEXone is 1.5 · 10⁻³ for unpolarized scenes and 2.9 · 10⁻³ for highly polarized scenes, compliant with the polarimetric accuracy requirement. This performance should enable SPEXone to deliver the data quality that enables unprecedented aerosol characterization from space on the NASA PACE mission.

Proceedings Article | 12 July 2019 Open Access

Open Access

Paper

Manufacturing and optical performance of silicon immersed gratings for Sentinel-5

Ralf Kohlhaas, Paul Tol, Ruud Schuurhof, Robert Huisman, Stephen J. Yates, Geert Keizer, René Wanders, Sander van Loon, Tonny Coppens, Mustafa Kaykisiz, Phillip Laubert, Peter Paul Kooijman, Aaldert van Amerongen, Luc Dubbeldam

Proceedings Volume 11180, 111801L (2019) https://doi.org/10.1117/12.2535976

KEYWORDS: Prisms, Wavefronts, Semiconducting wafers, Silicon, Wafer bonding, Sensors, Mirrors, Optical alignment, Manufacturing, Polarization

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Proceedings Article | 12 July 2019 Open Access

Open Access

Paper

SPEXone: a compact multi-angle polarimeter

Aaldert van Amerongen, Jeroen Rietjens, Jochen Campo, Ersin Dogan, Jos Dingjan, Raj Nalla, Jerome Caron, Otto Hasekamp

Proceedings Volume 11180, 111800L (2019) https://doi.org/10.1117/12.2535940

KEYWORDS: Aerosols, Telescopes, Mirrors, Sensors, Spectroscopy, Polarization, Modulation, Ocean optics, Optics manufacturing, Polarimetry

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We have developed a 6 dm³-sized optical instrument to characterize the microphysical properties of fine particulate matter or aerosol in the Earth atmosphere from low Earth orbit. Our instrument can provide detailed and worldwide knowledge of aerosol amount, type and properties. This is important for climate and ecosystem science and human health [1, 2]. Therefore, NASA, ESA and the European Commission study the application of aerosol instruments for planned or future missions. We distinguish molecular Rayleigh scattering from aerosol Mie-type scattering by analyzing multi-angle observations of radiance and the polarization state of sun light that is scattered in the Earth atmosphere [3]. We measure across the visible wavelength spectrum and in five distinct viewing angles between -50° and +50°. Such analysis has been traditionally done by rotating polarizers and band-filters in front of an Earth observing wide-angle imager. In contrast, we adopt a means to map the linear polarization state on the spectrum using passive optical components [4]. Thereby we can characterize the full linear polarization state for a scene instantaneously. This improves the polarimetric accuracy, which is critical for aerosol characterization, enabling us to distinguish for example anthropogenic from natural aerosol types. Moreover, the absence of moving parts simplifies the instrument, and makes it more robust and reliable. We have demonstrated this method in an airborne instrument called SPEX airborne [5, 6] in the recent ACEPOL campaign together with a suite of state-of-the art and innovative active and passive aerosol sensors on the NASA ER-2 high-altitude research platform [7]. An earlier report on the SPEX development roadmap was given in [8]. In this contribution we introduce SPEXone, a compact space instrument that has a new telescope that projects the five viewing angles onto a single polarization modulation unit and the subsequent reflective spectrometer. The novel telescope allows the observation of five scenes with one spectrometer, hence the name. We describe the optical layout of the telescope, polarization modulation optics, and spectrometer and discuss the manufacturability and tolerances involved. We will also discuss the modelled instrument performance and show preliminary results from optical breadboards of the telescope and polarization modulation optics. With SPEXone we present a strong and new tool for climate research and air quality monitoring. It can be used to study the effect of atmospheric aerosol on the heating/cooling of the Earth and on air quality. Also, SPEXone can improve the accuracy of satellite measurements of greenhouse gas concentrations and ocean color that rely on molecular absorption of reflected sunlight by providing detailed knowledge of the aerosol properties, required to accurately trace the light path in presence of scattering.
SPEXone is developed in a partnership between SRON Netherlands Institute for Space Research and Airbus Defence and Space Netherlands with support from the Netherlands Organisation for Applied Scientific Research (TNO) as a Dutch contribution to the NASA PACE observatory launching in 2022.

Proceedings Article | 20 November 2017 Open Access

Open Access

Paper

State of the art in silicon immersed gratings for space

Aaldert van Amerongen, Hélène Krol, Catherine Grèzes-Besset, Tonny Coppens, Ianjit Bhatti, Dan Lobb, Bram Hardenbol, Ruud Hoogeveen

Proceedings Volume 10564, 105642R (2017) https://doi.org/10.1117/12.2309092

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We present the status of our immersed diffraction grating technology, as developed at SRON and of their multilayer optical coatings as developed at CILAS. Immersion means that diffraction takes place inside the medium, in our case silicon. The high refractive index of the silicon medium boosts the resolution and the dispersion. Ultimate control over the groove geometry yields high efficiency and polarization control. Together, these aspects lead to a huge reduction in spectrometer volume. This has opened new avenues for the design of spectrometers operating in the short-wave-infrared wavelength band. Immersed grating technology for space application was initially developed by SRON and TNO for the short-wave-infrared channel of TROPOMI, built under the responsibility of SSTL. This space spectrometer will be launched on ESA's Sentinel 5 Precursor mission in 2015 to monitor pollution and climate gases in the Earth atmosphere. The TROPOMI immersed grating flight model has technology readiness level 8. In this program CILAS has qualified and implemented two optical coatings: first, an anti-reflection coating on the entrance and exit facet of the immersed grating prism, which reaches a very low value of reflectivity for a wide angular range of incidence of the transmitted light; second, a metal-dielectric absorbing coating for the passive facet of the prism to eliminate stray light inside the silicon prism. Dual Ion Beam Sputtering technology with in-situ visible and infrared optical monitoring guarantees the production of coatings which are nearly insensitive to temperature and atmospheric conditions. Spectral measurements taken at extreme temperature and humidity conditions show the reliability of these multi-dielectric and metal-dielectric functions for space environment. As part of our continuous improvement program we are presently developing new grating technology for future missions, hereby expanding the spectral range, the blaze angles and grating size, while optimizing performance parameters like stray light and wavefront error. The program aims to reach a technology readiness level of 5 for the newly developed technologies by the end of 2012. An outlook will be presented.

Proceedings Article | 20 November 2017 Open Access

Open Access

Paper

Antireflection and absorbing coatings for TROPOMI SWIR immersed grating

Hélène Krol, Grégory Chauveau, Didier Torricini, Catherine Grèzes-Besset, Aaldert van Amerongen

Proceedings Volume 10564, 1056438 (2017) https://doi.org/10.1117/12.2309073

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Proceedings Article | 25 September 2017 Open Access

Open Access

Paper

Spex the Dutch roadmap towards aerosol measurement from space

Aaldert van Amerongen, Jeroen Rietjens, Martijn Smit, Dennis van Loon, Hedser van Brug, Wencke van der Meulen, Marco Esposito, Otto Hasekamp

Proceedings Volume 10562, 105621O (2017) https://doi.org/10.1117/12.2296227

KEYWORDS: Aerosols, Polarization, Modulation, Sensors, Clouds, Polarimetry, Signal to noise ratio, Prototyping, Atmospheric modeling, Astronomical imaging

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Proceedings Article | 25 September 2017 Open Access

Open Access

Paper

Development and optical performance tests of the Si immersed grating demonstrator for E-ELT METIS

Ramon Navarro, Tibor Agócs, Lars Venema, Aaldert van Amerongen, Michiel Rodenhuis, Ruud W. Hoogeveen, Tonny Coppens, Bernhard Brandl, Ramon Vink

Proceedings Volume 10562, 1056257 (2017) https://doi.org/10.1117/12.2296128

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Proceedings Article | 22 July 2016 Paper

Paper

Optical tests of the Si immersed grating demonstrator for METIS

Tibor Agócs, Ramon Navarro, Lars Venema, Aaldert van Amerongen, Ruud W. Hoogeveen, Tonny Coppens, Govert Nieuwland, Michiel Rodenhuis, Bernhard Brandl, Ramon Vink

Proceedings Volume 9912, 991215 (2016) https://doi.org/10.1117/12.2234686

KEYWORDS: Diffraction gratings, Silicon, Semiconducting wafers, Wavefronts, Diffraction, Wafer-level optics, Spectrographs, Photomasks, Prisms, Bidirectional reflectance transmission function

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Proceedings Article | 7 October 2015 Paper

Paper

Performance of silicon immersed gratings: measurement, analysis, and modeling

Michiel Rodenhuis, Paul Tol, Tonny Coppens, Phillip Laubert, Aaldert van Amerongen

Proceedings Volume 9626, 96261M (2015) https://doi.org/10.1117/12.2191266

KEYWORDS: Semiconducting wafers, Prisms, Silicon, Inspection, Diffraction gratings, Spectrographs, Infrared radiation, Polishing, Scanning electron microscopy, Optical design

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Proceedings Article | 21 October 2014 Paper

Paper

Design, simulation and test of silicon immersed gratings: key to compact spectrometers in the short-wave infrared

Aaldert van Amerongen, Paul J. Tol, Tonny H. Coppens, Ruud Schuurhof, Phillip Laubert, Jos Ruijter, Ruud W. Hoogeveen

Proceedings Volume 9241, 92411H (2014) https://doi.org/10.1117/12.2067203

KEYWORDS: Diffraction gratings, Optical design, Silicon, Prisms, Manufacturing, Spectrometers, Semiconducting wafers, Reflection, Short wave infrared radiation, Diffraction

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Proceedings Article | 28 July 2014 Paper

Paper

A set of innovative immersed grating based spectrometer designs for METIS

Tibor Agócs, Ramon Navarro, Lars Venema, Aaldert van Amerongen, Paul J. Tol, Hedser van Brug, Bernhard Brandl, Frank Molster, Stephen Todd

Proceedings Volume 9151, 91511L (2014) https://doi.org/10.1117/12.2055404

KEYWORDS: Mirrors, Optical design, Optics manufacturing, Spectroscopy, Prisms, Sensors, Silicon, Monochromatic aberrations, Spectrometer engineering, Diffraction gratings

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Proceedings Article | 13 September 2012 Paper

Paper

Development of silicon immersed grating for METIS on E-ELT

Aaldert van Amerongen, Tibor Agocs, Hedser van Brug, Govert Nieuwland, Lars Venema, Ruud W. Hoogeveen

Proceedings Volume 8450, 84502T (2012) https://doi.org/10.1117/12.925612

KEYWORDS: Silicon, Diffraction gratings, Semiconducting wafers, Prisms, Spectroscopy, Diffraction, Optical design, Manufacturing, Mirrors, Polishing

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Proceedings Article | 13 October 2010 Paper

Paper

Development of immersed diffraction grating for the TROPOMI-SWIR spectrometer

A. van Amerongen, H. Visser, R. J. Vink, T. Coppens, R. Hoogeveen

Proceedings Volume 7826, 78261D (2010) https://doi.org/10.1117/12.869018

KEYWORDS: Diffraction gratings, Silicon, Spectroscopy, Diffraction, Polarization, Optical design, Lithography, Spectral resolution, Photomasks, Anisotropic etching

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Showing 5 of 19 publications

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