Space Optics Instrument Design & Technology 2018

Optical CAD Instrument Modelling and Analysis - Dmitriy Worontsow
Within this presentation the participants will get a general overview of the optical software CodeV. They will learn how to use the software, building lens systems and performing the performance analysis of the optical design. An introduction to lens system optimization and tolerance analysis will be given. The course is including both the theoretical part as well as practical implementation in the software. The participants will have the possibility to analyze and optimize all the examples of the course on their own laptop.

Manufacturing Technologies for Space Optics - Roland Geyl
We will review in this course module the subject of precision optical manufacturing for space optics. After first detailing what is a ‘good’ optical surface and doing a brief historical overview, we will present the generic optical manufacturing process and then review the various technologies dedicated to the production of quality optical surface. Glass, metal and ceramic will be addressed. Grinding-lapping-polishing is the main subject but other techniques like replication, single point diamond turning and material deposition technique will also be addressed. The typical defects of optical surfaces, their impacts and prevent/repairs actions will be reviewed to support student future real life.

Optics packaging Technologies for harsh environment - Erik Beckert
Not only the design, but also the packaging of optical systems is a key factor for highly performant and reliable, robust systems. This is of interest in particular in harsh environments, such as aviation and space, but also vacuum science and high power laser machining. Packaging of optical systems poses various challenges - different materials have to be joined together, components and their optical performance are stress and alignment sensitive, heat from active sources and conversion materials needs to be dissipated, and steep temperature gradients causing thermomechanical stress can occur. Well designed and optimized packaging and bonding technologies address these needs.
The talk will focus on bonding techniques for metallic and non-metallic, amorphous and crystalline materials, emphasizing on the development and application chain from bonding geometry design, optimization by simulation of stress and the resulting birefringent or laser-optical performance, and practical issues of processing and equipment when applying different bonding technologies. Specific technologies to be discussed are gluing, soft soldering by means of laser reflow, hydrophilic bonding and plasma assisted bonding as well as two-photon absorption based laser welding. The basics as well as design and parametrization of these techniques will be discussed, followed up by boundary conditions and restrictions. Examples will demonstrate the application of the different technologies in reality. Amongst them is the green laser for the Raman experiment of the upcoming 2020 ExoMars Mission, a nanosecond fiber laser for a space LIDAR and an entangled photon source for a satellite quantum payload.

Imaging Optics Design with Freeform Optics - Jannick Roland
In this course, we will first provide an oveview status on freeform optics from a design, fabrication and metrology viewpoint. We will then detail a methodology for design and review some examples of freeform optics from design to manufacture.

Freeform Optics Verification - Christopher Evans
This series of lectures will start from fundamentals -- calibration, uncertainty and traceability in freeform optics metrology. Design intent should be captured in the specification of the optic, for example in a drawing that is in accordance with ISO 10110. We will discuss freeform optics specifications that flow down to measurands that can be estimated en route to establishing that a specific optical surface meets the design intent. Does the designer have a specific manufacturing process in mind? Can this be captured in the surface specification -- and should it be? We will review the range of optics metrology methods available and discuss tools for rational comparison between available options. "Design for Metrology" will be a central theme. We will review commercially available technologies and emerging methods.

Lithographic Grating Technology - Uwe Zeitner
Gratings are key components in space-borne spectrometers for earth observation and scientific missions. Their optical properties determine the achievable spectral resolution and signal quality of the instrument. Based on the specific requirements of contemporary spectrometers an overview of state-of-the-art fabrication technologies for the required high-end optical gratings will be given. This includes methods like ruling, holography, and direct write lithographic structuring. Their potential and limitations for the realization of a desired grating profile and related properties like high polarization independent diffraction efficiencies, good wave-front qualities, and low stray-light levels will be discussed. Different examples of gratings tailored for specific ESA space missions like GAIA, Sentinel-4/5, or DESIS will be shown.

Space Coating Manufacturing and Qualification - Uwe Schallenberg
The lecture starts with an overview of optical coatings for space applications, like anti-reflection, high-, low- and band-pass coatings. Rules of thumb for the general coating design are discussed and a brief excurse in theory and praxis of thin-film optical coatings in general will be provided. Emphasis will be put on the state-of –the-art manufacturing technology for the manufacturing of hard optical coatings, especially the sputtering technology and the ion-assisted deposition technology. Additional necessary technology for the on-line monitoring of coating layer thickness will be reviewed. A third major point is related to coating qualification for space applications. Typical qualification requirements and lessons learned from space projects will be reported.

Polarization Scrambler – Concepts, Optical Design, Manufacturability and Performances - Jerome Caron
Polarization scramblers are optical devices that depolarize light, and alter as little as possible light propagation so that they can be used in imaging instruments. Scramblers from the class of spatial pseudo-depolarizers are compact, passive components with high performance that are well suited for space applications. They have (or are currently) been built for several spectro-imagers to make the measurements insensitive to polarization: OMI, Envisat/Meris, Sentinel-3/OLCI, Sentinel-4/UVN, Sentinel-5p/Tropomi, Sentinel-5. In this course we will present their design, performance, manufacturing and testing. The Dual Babinet [1] is the most important design and will be assumed for the general discussion. Other types such as the HV depolarizer, the Meris scrambler, the plane-parallel scrambler and a few recent patents will be also presented.
[1] R.A.Chipman, J.P.McGuire, Analysis of spatial pseudodepolarizers in imaging systems, Opt. Eng. vol29 n12, pp1478-1484 (1990).

Optically Rough Surface Scatter Measurements and Modelling - Monika Kroneberger
Light scattering caused by the imperfections of optical and mechanical surfaces can critically affect the performance of space optical instruments (image quality, losses). It is therefore very important to predict and measure stray light performance of the optical instrument accurately.
This lecture is focusing on light scattering of mechanical surfaces and of diffusers. Special emphasis will be put on how to measure and model optically rough surface scatter. A second part will focus on the minimization of mechanical surface scatter by "black"coatings and a review of achievable performances.

Structural-Thermal-Optical Performance (STOP) Analysis of the Euclid Space Telescope - Sergio Mottini
Success of ESA’s Euclid cosmology mission depends on the stability of the telescope under loads transmitted from its environment, including the spacecraft bus. STOP analysis is the tool used to verify compliance with the tight image quality budgets of the focal plane instruments. The analysis proceeds through three coordinated sets of mathematical models to calculate, in sequence, temperature distributions, displacement and/or distortion of the optical elements, point spread functions at selected locations on the focal planes, and the resulting optical figures of merit. After a brief presentation of the mission objectives, the telescope and satellite design, and the environmental boundary conditions, the lecture will describe in some detail the procedure adopted, the results achieved and the lessons learnt at the time of the project’s Critical Design Review.

AIT of On- and Off-axis telescopes - Matthias Erdmann
The optical alignment of the telescope is a key activity of the AIT process of On- and Off-axis telescopes. The method described and practiced in the lecture is based on the fact that any alignment activity (shifting and tilting of optical elements) influences only the low order aberrations of the optical system. For the alignment the Wave Front Error (WFE) of the telescope is measured (e.g. by auto-collimation) and decomposed in low order aberration contributions. Based on analysis of the as-built model of the telescope and probing of the pre-aligned telescope optics sensitivities of low order WFE contributions to all optical alignment Degree Of Freedoms can be evaluated. Based on these sensitivities the next step of alignment improvement can be calculated, executed and verified. Recursive application of these technique converges to a perfect optical alignment after two or three iterations. For Korsch type telescopes including Three Mirror Anastigmats (TMA) the typical aberration and aberration sensitivities field gradients are discussed and their utilisation for the alignment is described and practiced.

Detector Technology - Kyriaki Minoglou
The major objective of this lecture is to make the participants familiar with the different types of detectors that can be used in space instruments applications. Design, technology and characterization of detectors and the relevant topics will be discussed.

Hands-on Activity - Bernd Harnisch, Volker Kirschner
The task of the hands-on activity is to design, manufacture and test a telecentric projection lens. Such lens type might be part of the payload for planetary exploration. The participants will work in groups of two. For the design the participants can make use of the optical software CodeV, for which a 1-day introduction is given in the Begin of the course. For the hardware implementation three stock lenses from Edmund Optics and structural material will be provided. The lens performances in MTF and telecentricity shall be verified by test.