A novel athermal approach for high-performance cryogenic metal optics

Details A novel athermal approach for high-performance cryogenic metal optics A novel athermal approach for high-performance cryogenic metal optics

Jul 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010spie.7739e.141r&link_type=abstract

Modern Technologies in Space- and Ground-based Telescopes and Instrumentation. Edited by Atad-Ettedgui, Eli; Lemke, Dietrich.

Physics

Optics

Scientific paper

This paper describes a new athermal approach for high performance metal optics, particularly with regard to extreme environmental conditions as they usually may occur in terrestrial as well as in space applications. Whereas for mid infrared applications diamond turned aluminium is the preferred mirror substrate, it is insufficient for the visual range. For applications at near infrared wavelengths (0.8 μm - 2.4 μm) as well as at on cryogenic temperatures (-200°C) requirements exist, which are only partially met for diamond turned substrates. In this context athermal concepts such as optical surfaces with high shape accuracy and small surface micro-roughness without diffraction effect and marginal loss of stray light, are of enormous interest. The novel, patented material combination matches the Coefficient of Thermal Expansion (CTE) of an aluminium alloy with high silicon content (AlSi, Si >= 40 %) as mirror substrate with the CTE of the electroless nickel plating (NiP). Besides the harmonization of the CTE (~ 13 * 10-6 K-1), considerable advantages are achieved due to the high specific stiffness of these materials. Hence, this alloy also fulfils an additional requirement: it is ideal for the manufacturing of very stable light weight metal mirrors. To achieve minimal form deviations occurring due to the bimetallic effect, a detailed knowledge of the thermal expansion behavior of both, the substrate and the NiP layer is essential. The paper describes the reduction of the bimetallic bending by the use of expansion controlled aluminium-silicon alloys and NiP as a polishing layer. The acquisition of CTE-measurement data, the finite elements simulations of light weight mirrors as well as planned interferometrical experiments under cryogenic conditions are pointed out. The use of the new athermal approach is described exemplary.

Affiliated with

Also associated with

No associations

Rating

A novel athermal approach for high-performance cryogenic metal optics does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A novel athermal approach for high-performance cryogenic metal optics, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A novel athermal approach for high-performance cryogenic metal optics will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1386422