ICP polishing of silicon for high quality optical resonators on a chip

Author(s): A. Laliotis, Michael Trupke, J. P. Cotter, M. Kraft, G. Lewis, E.A. Hinds

Journal: J. Micromech. Microeng.

Volume: 22

Page(s): 125011

Year: 2012

DOI Number: 10.1088/0960-1317/22/12/125011

Link: Link to publication


Miniature concave hollows, made by wet etching silicon through a circular mask, can be used as mirror substrates for building optical micro-cavities on a chip. In this paper we investigate how ICP polishing improves both shape and roughness of the mirror substrates. We characterise the evolution of the surfaces during the ICP polishing using white-light optical profilometry and atomic force microscopy. A surface roughness of 1 nm is reached, which reduces to 0.5 nm after coating with a high reflectivity dielectric. With such smooth mirrors, the optical cavity finesse is now limited by the shape of the underlying mirror.

Note: http://arxiv.org/abs/1208.5647

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