Abstract
In this study four aluminium and brass freeform mirrors
used as fiber optic spectrometer probes were micro-milled
and ALD SiO2 coating was added. Freeform surfaces were
designed by combining optical modeling with the
mechanical structure. Moore 350 FG ultra precision
machine tool was used for milling the freeform parts. To
evaluate the surface roughness of the machining one
aluminium and one brass freeform mirror also contained a
40 mm radius reference lens. The surface roughness's of
parts containing reference lenses were analysed prior to
coating them with SiO2 on atomic layer deposition (ALD)
device. The uncoated and coated reference lenses were
measured with optical profiler. The Ra values of
micro-milled reference lenses on uncoated aluminium and
brass surfaces were in good correlation to theoretical
values. On uncoated aluminium mirror surface roughness Ra
was 6.8 nm and for uncoated brass mirror Ra was 5.7 nm.
On coated aluminium mirror surface roughness Ra was 5.2
nm and on coated brass mirror Ra was 5.5 nm. For the
testing of the spectral functionality of the system the
mirrors were coupled to a fiber-optic UV-VIS
spectrometer. Spectral measurements were done on coated
and uncoated mirrors with several different coloured
reflectance standards. Spectral measurements show that
SiO2 coating affects the reflectance characteristics of
both mirror surfaces while maintaining high reflectivity
characteristics.
Original language | English |
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Title of host publication | Proceedings of the |
Subtitle of host publication | 13th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2013 |
Editors | R. Leach, P. Shore |
Publisher | Euspen |
Pages | 35 - 38 |
ISBN (Print) | 978-095667902-4 |
Publication status | Published - 2013 |
MoE publication type | Not Eligible |
Event | 13th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2013 - Berlin, Germany Duration: 27 May 2013 → 31 May 2013 |
Conference
Conference | 13th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2013 |
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Abbreviated title | EUSPEN 2013 |
Country/Territory | Germany |
City | Berlin |
Period | 27/05/13 → 31/05/13 |
Keywords
- aluminium
- atomic layer deposition
- brass
- coatings
- lenses
- milling
- mirrors
- optical testing
- precision engineering
- reflection
- spectometers
- mechanical structures
- optical characteristics
- reflectance characteristics
- reflectance standards
- spectral measurement
- ultra-precision machine tools
- UV-vis spectometer