High intensities

The generation of high intensities requires high pulse energies, a short pulse duration and excellent beam focusability. In this respect, a fundamental advantage of UV laser sources is their capability to focus the radiation much tighter than IR devices can do (focal area ~ λ²).

UV high brightness laser systems apply excimer modules to amplify the frequency converted radiation of conventional short pulse lasers. A specific advantage of excimer amplifiers is offered by their low density amplifying medium, insuring negligible phase front distortions during amplification, thus resulting in excellent output beam quality.

In order to meet the high demands of reaching highest intensities in the UV, a special twin-tube amplifier device was designed with two discharge channels. A spatial filter implemented between the discharge tubes provides very efficient ASE (amplified spontaneous emission) suppression. Furthermore, a grating pulse compressor applied to the pulses in front of the second discharge tube allows control of the temporal pulse profile at relatively modest energy levels. This system architecture results in output pulse energies of up to 50 mJ with a typical pulse duration of 250 fs in a nearly diffraction limited beam, thus enabling to reach focused intensities of > 10¹⁹ W/cm² ermöglicht (UV femtosecond amplifier TwinAmp)

Figure 1: UV high brightness system