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

Athanasios Laliotis (1) , Michael Trupke (2) , Joe C. Cotter (3) , Gareth Lewis (4) , Michael Kraft (5) , E. A. Hinds (6)

1 LPL - Laboratoire de Physique des Lasers
2 AtomChip Group
3 Quantum Optics and Laser Science, Blackett Laboratory
4 ECS - School of Electronics and Computer Science
5 ECS Department - University of Southampton
6 Centre for Cold Matter

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.

Domains: Optics / Photonic

Athanasios Laliotis, Michael Trupke, Joe C. Cotter, Gareth Lewis, Michael Kraft, et al.. ICP polishing of silicon for high quality optical resonators on a chip. Journal of Micromechanics and Microengineering, 2012, 22 (12), pp.125011. ⟨hal-00796166⟩