Work

Simultaneous atmospheric pressure plasma jet etching and laser irradiation for ultra-precise optical glass processing

Year: 2024

Type: article

Abstract: The use of beam-based technologies to process optical elements with nanoscale precision enables the fabrication of freeform surfaces. In particular, atmospheric pressure plasma jets (APPJs) have desirable properties, e.g., depth precision < 5 nm, low surface roughness and processing at atmospheric conditions. However, the composition of optical glasses and glass ceramics, containing metal oxides, leads to the formation of non-volatile reaction products that remain on the substrate surface. These residues reduce the etching rate and cause severe roughening of the surface. Laser irradiation has already been demonstrated as a promising option for removing the residual layer and the aim of the current work is to integrate it into the APPJ system for simultaneous processing. Therefore, an excimer laser (λ = 248 nm; tPulse = 20 ns) with a maximum pulse frequency of 100 Hz was added to a plasma jet setup and experiments with varying laser fluences as well as laser frequencies were performed on N-BK7 substrates. White light interferometry was used to analyse the samples. The experiments showed an improved etching result with higher removal rates for the combined process at high laser pulse frequency (100 Hz) and fluences in the range of 0.1-0.45 J·cm-2.

Source: Springer Link (Chiba Institute of Technology)

DOI: 10.1051/epjconf/202430903022/pdf

Authors: Robert Heinke, Thomas Arnold, Martin Ehrhardt, Pierre Lorenz, Klaus Zimmer

Institutions: Leibniz Institute of Surface Engineering, Technische Universität Dresden

Language: English

Topic: Laser Material Processing Techniques

Subfield: Computational Mechanics

Field: Engineering

Domain: Physical Sciences

Open Access status: green

Funder: Deutsche Forschungsgemeinschaft

Award: Laserstimulierte reaktive AtmosphärendruckPlasmajetÄtzprozesse zur Ultrapräzisionsbearbeitung optischer Gläser (LasPlasJet)