Regular papers

Polishing of optical media by dielectric barrier discharge inert gas plasma at atmospheric pressure

¹ University of Applied Sciences and Arts, Laboratory of Laser and Plasma Technologies, Von-Ossietzky-Straße 99, 37085 Göttingen, Germany
² Fraunhofer Institute for Surface Engineering and Thin Films, Application Center for Plasma and Photonics, Von-Ossietzky-Straße 99, 37085 Göttingen, Germany
³ Roth & Rau AG, An der Baumschule 6-8, 09337 Hohenstein-Ernstthal, Germany

^* gerhard@hawk-hhg.de

Received: 20 November 2013
Accepted: 10 December 2013

Abstract

In this paper, surface smoothing of optical glasses, glass ceramic and sapphire using a low-power dielectric barrier discharge inert gas plasma at atmospheric pressure is presented. For this low temperature treatment method, no vacuum devices or chemicals are required. It is shown that by such plasma treatment the micro roughness and waviness of the investigated polished surfaces were significantly decreased, resulting in a decrease in surface scattering. Further, plasma polishing of lapped fused silica is introduced. Based on simulation results, a plasma physical process is suggested to be the underlying mechanism for initialising the observed smoothing effect.