Narrow band excimer or molecular fluorine laser having an output coupling interferometer

US6421365B1 · kind B1 · utility

Assignee

• Lambda Physik AG · DE

Inventors

• Juergen Kleinschmidt · Oettingen, DE
• Peter Lokai · Oettingen, DE

Key dates

• Filing date: Nov 17, 2000
• Grant date: Jul 16, 2002
• Expiry date: Nov 17, 2020

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S3/225
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An excimer or molecular fluorine laser includes a discharge chamber filled with a gas mixture, multiple electrodes within the discharge chamber connected to a power supply circuit for energizing the gas mixture, and a resonator including the discharge chamber and a pair of resonator reflectors for generating an output laser beam. One of the resonator reflectors is an output coupling interferometer including a pair of opposing reflecting surfaces tuned to produce a reflectivity maximum at a selected wavelength for narrowing a linewidth of the output laser beam. One of the pair of opposing reflecting surfaces is configured such that the opposing reflecting surfaces of the interferometer have a varying optical distance therebetween over an incident beam cross-section which serves to suppress outer portions of the reflectivity maximum to reduce spectral purity. Preferably, this surface is non-planar, and may include a step, a recess or a raised or recessed curved portion of a quarter wavelength in height or depth, respectively.