Molecular fluorine (F2) laser with narrow spectral linewidth

US6426966B1 · kind B1 · utility

Assignee

• Lambda Physik AG · DE

Inventors

• Dirk Basting · Fort Lauderdale, US
• Sergei V. Govorkov · Mountain View, US
• Uwe Stamm · Göttingen, DE

Key dates

• Filing date: Sep 8, 2000
• Grant date: Jul 30, 2002
• Expiry date: Jan 24, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S3/2258
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A molecular fluorine (F2) laser is provided wherein the gas mixture comprises molecular fluorine for generating a spectral emission including two or three closely spaced lines around 157 nm. An etalon provides line selection such that the output beam only includes one of these lines. The etalon may also serve to outcouple the beam and/or narrow the selected line. Alternatively, a prism provides the line selection and the etalon narrows the selected line. The etalon may be a resonator reflector which also selects a line, while another element outcouples the beam. The etalon plates comprise a material that is substantially transparent at 157 nm, such as CaF2, MgF2, LiF2, BaF2, LiF, SrF2, quartz and fluorine doped quartz. The etalon plates are separated by spacers comprising a material having a low thermal expansion constant, such as invar, zerodur®, ultra low expansion glass, and quartz. A beam expander is preferably provided before the etalon for expanding the beam before the beam is incident on the etalon. The beam expander is preferably configured to reduce the divergence of the beam.