Presently TNO/Demcon are manufacturing nine Laser Projection Systems (LPS). TNO is responsible for the design and manufacturing of the Optical Tube Assembly (OTA), the baseplate and the LPS cover. Demcon designed and manufactured the Beam Conditioning and Diagnostic System (BCDS). TNO is also responsible for the system performance and its verification tests.
Six units will be used on the ELT. The other three are destined for the VLT. That will allow the operation of the adaptive mirrors enabling unprecedented image quality of the telescopes. The design of this system is based on the four laser guide stars units as used on the VLT.
The system has been upgraded considerably compared to the units used for the VLT. Its FOV has increased to 7 arcmin (half cone). The laser power goes up to 50W and the BCDS has been completely redesigned. The BCDS is located between the laser source and the OTA that produces the Ø300 mm output beam. Maintainability and accessibility of the system have also been much improved.
Prime qualities are its insensitivity to temperature changes (static and dynamic), its accuracy and its FOV. Assembly of the first unit is finished and in January the acceptance testing of the system started. The first unit is expected to be delivered to ESO in autumn 2024.
Remote sensing of aerosols requires spectropolarimetric information over different viewing angles with demanding polarimetric accuracy and growing interest for smaller designs. In this paper, we investigate an instrument design that implements a metasurface filter which enables both functions simultaneously, allowing further miniaturization and integrability. The instrument offers 1 km ground sampling distance over its entire field of view, in Low Earth Orbit, and the concept makes use of six modules to cover the wide field of view requested for aerosol retrieval with a total of seven radiation-resistant lenses. This choice enables an optical volume per module under 50mm × 50mm × 150mm and smaller relative angles of incidence. The filters are designed to cover six spectral bands from 443 nm to 870 nm with a spectral resolution of 2 nm to 5 nm. The wide spectral band is achieved by using three distributed Bragg reflectors with bandpass filters, integrated in one double-cavity structure that can be glued on a CCD/CMOS sensor. The two cavities, operating as a metasurface, contain scatterers of different dimensions enabling the fine-tuning of the spectral resonance and the polarization filtering. Multiscale forward modeling techniques are employed for the estimation of the polarimetric accuracy with optical aberrations and realistic coatings. Using radiance values from the PACE mission, polarimetric errors and SNR at each pixel are estimated and compared to requirements of state-of-the-art missions.
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 using a number of coatings. Three black UV mirror coatings absorb light with a wavelength above 370nm. Together, these achieve more than four orders suppression of long wave out-of-band light. A lowpass transmission filter with a position dependent cut-off wavelength is deposited on the last lens surface, directly in front of the detector. At the position where short wavelength light passes the filter, longer wavelength in-band stray light and ghosts are blocked. A simulation predicts that this graded filter reduces ghosting by a factor 20 and scatter related stray light by factor 30.
Both ESA and the EC have identified the need for a supply chain of CMOS imagers for space applications which uses solely European sources. An essential requirement on this supply chain is the platformization of the process modules, in particular when it comes to very specific processing steps, such as those required for the manufacturing of backside illuminated image sensors. This is the goal of the European (EC/FP7/SPACE) funded project EUROCIS. All EUROCIS partners have excellent know-how and track record in the expertise fields required. Imec has been leading the imager chip design and the front side and backside processing. LASSE, as a major player in the laser annealing supplier sector, has been focusing on the optimization of the process related to the backside passivation of the image sensors. TNO, known worldwide as a top developer of instruments for scientific research, including space research and sensors for satellites, has contributed in the domain of optical layers for space instruments and optimized antireflective coatings. Finally, Selex ES, as a world-wide leader for manufacturing instruments with expertise in various space missions and programs, has defined the image sensor specifications and is taking care of the final device characterization. In this paper, an overview of the process flow, the results on test structures and imagers processed using this platform will be presented.
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