Damage Formation On Fused Silica Illuminated With Ultraviolet-Infrared Femtosecond Pulse Pairs

Keywords

Avalanche ionization; Femtosecond laser machining; Fused silica; IR pulse; Multiphoton ionization; UV pulse

Abstract

We investigate damage formation on the surface of fused silica by two femtosecond laser pulses, a tightly focused 266 nm (UV) pulse followed by a loosely focused 800 nm (IR) pulse. We show that the damage size is determined by the UV pulse, and only a small fraction of the normal UV damage threshold energy is needed to cause damage when combined with the properly delayed IR pulse. Our results, analyzed with a rate equation model, suggest that the UV pulse generates seed electrons through multiphoton absorption and the IR pulse utilizes these electrons to cause damage by avalanche ionization. By tuning such parameters like pulse energy, time delay, IR pulse duration and polarization, we further demonstrate that damage profile can be controlled.

Publication Date

1-1-2015

Publication Title

Proceedings of SPIE - The International Society for Optical Engineering

Volume

9511

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1117/12.2182633

Socpus ID

84943390374 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84943390374

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