![]() ![]() They compensate for thermal expansion effect between aluminum structure (SLITA side) and Invar/silicon on double slit device side, respectively (see below). The mechanical mount of the double slit device to the slit assembly (SLITA) is realized via mechanical flexures. At several positions, dedicated, geometrical structures coated with black diffuse coatings contribute to suppression of out-of-field stray light. Both mirrors are equipped with very steep optical band-pass filter coatings, which suppress out-of-band radiation and thus in-field stray light. Thus, HRS and LRS optical paths are separated. Shortly behind the double slit, two folding mirrors (HR Fold Mirror and LR Fold Mirror, resp.) deflect the respective optical beams in two ‘opposite’ directions. The double slits (44.1 mm x 0.084 mm each) are separated by 4.5 mm and must be accurately manufactured and registered with respect to each other. The double slit assembly is placed at the focus plane of the telescope (intermediate focus of the instrument).Ī schematic of the optical architecture of the FLEX instrument, and the place of the Slit Assembly within is depicted in the FLEX optical layout in Figure 1. The overlapped spectral range has been introduced to simplify the interband co-registration between the two spectrometers.Įarth radiation is focused by a telescope onto the slit plane with (F# = 3.1). ![]() It will have a sampling of 0.1 nm in the oxygen bands (759–769 nm and 686–697 nm) and 0.5–2.0 nm in the red edge, chlorophyll absorption and PRI (Photochemical Reflectance Index) bands. The operative spectral regions are: 500 – 758 nm for LR and 677 – 780 nm for HR. įLEX instrument contains two spectrometers called High Resolution (HR) and Low Resolution (LR) spectrometer, respectively. By quantifying vegetation fluorescence, the photochemical reflectance index, the surface temperature, the FLEX mission concept will provide the most innovative and unique set of measurements to increase our understanding of actual photosynthetic efficiency, and the status of vegetation health and plant performance, while addressing related societal challenges previously identified. The FLEX mission will map vegetation fluorescence to quantify photosynthetic activity. the thermal vacuum test, the shock test, and the vibration test, are discussed. The results of environmental tests of the Double slit device Breadboard, i.e. The manufactured slits are coated with a black coating layer to reach the specified optical reflectivity and the optical density. The overall manufacturing process is the result of an extended technology development phase. It is based on the adaptation of lithographic structuring techniques for etching of Silicon wafers. the absolute slit width accuracy of less than 2 μm peak to valley, and slit planarity of less than 10 μm peak to valley. A dedicated lithographic structuring process chain was developed for the manufacturing of the double slit to fulfill a number of challenging requirements i.e. The slit position is aligned to mechanical interfaces to meet the tight positioning requirements. ![]() This device is designed to mount a silicon double slit chip into a mechanical holder providing mechanical and gauge interfaces to the slit assembly. The main focus of the paper is on the development and realization of the double slit device. We demonstrate solutions in design and manufacturing techniques as well as achieved performance under thermal and mechanical loads. High alignment and stability requirements, as well as stringent envelope restrictions are driving the mechanical design of the Slit Assembly. The paper presents design and implementation of its optical key components, which are a highly precise double slit and two mirrors achieving spatial channel separation and spectral filtering. Two different input beams for the Low- and the High-resolution spectrometer, respectively, will be generated by the Slit assembly. The high precision Slit Assembly is a key component of the FLEX instrument. ![]()
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