Development and fabrication of a hyperspectral, mirror based IR-telescope with ultra-precise manufacturing and mounting techniques for a snap-together system assembly

Risse, Stefan; Scheiding, Sebastian; Gebhardt, Andreas; Damm, Christoph; Holota, Wolfgang; Eberhardt, Ramona; Tünnermann, A.

doi:10.1117/12.898025

Cited by 18 publications

(12 citation statements)

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“…Tolerances between mounting features and the optical element in the µm-range, arc second-range respectively are mandatory for a simplified optics alignment. Risse et al 18 demonstrated a "snap-together" assembly of a IR mirror telescope with diffraction limited performance based on this approach.…”

Section: Alignment Of the Point Cloudmentioning

confidence: 98%

Freeform mirror fabrication and metrology using a high performance test CGH and advanced alignment features

et al. 2013

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The metrology of mirrors with an off-axis aspheric or freeform shape can be based on optical testing using a Computer Generated Hologram as wavefront matching element in an interferometric setup. Since the setup can be understood as optical system consisting of multiple elements with six degrees of freedom each, the accuracy strongly depends on the alignment of the surface under test with respect to the transmission element of the interferometer and the micro optics of the CGH. A novel alignment approach for the relative positioning of the mirror and CGH in six degrees of freedom is reported. In the presented work, a proper alignment is achieved by illuminating alignment elements outside the Clear Aperture (CA) of the optical surface with the help of auxiliary holograms next to the test CGH on the substrate. The peripheral holograms on the CGH substrate are used to generate additional phase maps in the interferogram, that indicate positioning errors. Since the reference spheres represent the coordinate system of the mirror and are measured in the same precision as the optical surface, the registration and shape has to be appropriate to embody the mirrors coordinate system. The alignment elements on the mirror body are diamond machined using freeform turning or micro milling processes in the same machine setup used for the mirror manufacturing. The differences between the turning and milling of alignment lenses is discussed. The novel approach is applied to correct the shape error of a freeform mirror using ultra precision machining. The absolute measurement of the quality of freeform mirror shapes including tilt and optical power is possible using the presented alignment concept. For a better understanding, different metrology methods for aspheres and freeforms are reviewed. To verify the novel method of alignment and the measurement results, the freeform surface is also characterized using ultra high accuracy 2½D profilometry. The results of the different techniques for the absolute measurement of freeforms are compared

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Section: Alignment Of the Point Cloudmentioning

confidence: 98%

Freeform mirror fabrication and metrology using a high performance test CGH and advanced alignment features

et al. 2013

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“…Furthermore, optical and mechanical reference structures on the mirrors may be manufactured in the same SPDT run. This strategy allows for a significantly simplified adjustment of the optical system [11,12]. The respective duolith mirrors of the DESIS instrument are depicted in Fig.…”

Section: A Mirror Designmentioning

confidence: 99%

“…These elements will be finished by single-point diamond fly-cutting [11,12] in a single machining run. They will be used to define a high precision starting point for the adjustment of the mirrors.…”

Section: B Instrument Housingmentioning

confidence: 99%

Design of an imaging spectrometer for earth observation using freeform mirrors

Peschel

Damm

Beier

et al. 2017

International Conference on Space Optics — ICSO 2016

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“…Metal optics has proven to be advantageous in respect of using conventional CNC and ultra-precision fabrication methods to realize complex and light-weighted instrument structures. Moreover, the mirror designs can be effectively optimized for a deterministic system assembly and optimization [2]. Limitations in terms of dimensional stability over temperature and time are mainly given by the inherent material properties (figures of merit) of the substrate material in interaction with the polishing layer.…”

Section: Introductionmentioning

confidence: 99%