Zero transmission and very low reflection can be obtained on the whole visible and near IR ranges with a metal-dielectric stack deposited on a transparent substrate. In this case, high absorption occurs within the bulk of the multilayer. Calculation shows that two materials are sufficient to have expected broad-band properties when the metal is associated with a low index dielectric. Suitable design is reached with a eight layer stack including a medium reflectance metal. The total metric thickness of this multilayer is about 0.5 micrometers . Thus this optical coating is convenient for space microbafflers involved in detector arrays or other applications in the field of parasitic light. Electron Beam Deposition process was used to fabricate these metal- dielectric components. Experimental results are presented. They show an absorption around 0.995 in the whole visible range. The achromatic behavior is successfully performed. With a modified design, we can enhance absorption in narrower spectral ranges. Much higher values of absorption are then reached and presented in this paper.

Date Published: 7 September 1999
PDF: 8 pages
Proc. SPIE 3738, Advances in Optical Interference Coatings, (7 September 1999); doi: 10.1117/12.360071

Published in SPIE Proceedings Vol. 3738:
Advances in Optical Interference Coatings
Claude Amra; H. Angus Macleod, Editor(s)