Efficient 193 nm generation by eighth harmonics of Er{sup}(3+) doped fiber amplifier

摘要

Deep-UV laser sources, particularly those operating at a wavelength of 193 nm, have been in great demand for use in micro-lithographic applications, medical applications, and many other applications that require high photon energy. In addition to the ArF excimer laser, several different solid-state 193 nm laser systems have been demonstrated. Most of these systems, however, are based on the Q-switched laser and/or tunable lasers, and require complex laser setups. By contrast, UV sources based on fiber lasers and amplifiers are compact and have robust characteristics. We report the narrow-band 193 nm sources using eighth-harmonic generation from the output of an erbium-doped fiber amplifier (EDFA) at 1547 nm. The conversion efficiency from the fundamental, 1547 nm, to 193 nm is 7.0%. To our knowledge, this represents the highest conversion efficiency ever achieved for 193 nm generation by a frequency conversion system.