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Hoffmann, Martin
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Hoffmann, Martin
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Voici les éléments 1 - 10 sur 23
- PublicationMétadonnées seulementUltrafast thin-disk laser with 80 ?J pulse energy and 242 W of average power(2014)
; ; Keller, Ursula - PublicationAccès libreUltrafast thin-disk laser with 80 µJ pulse energy and 242  W of average power(2014)
; ; Keller, UrsulaWe present a semiconductor saturable absorber mirror (SESAM) mode-locked thin-disk laser generating 80 µJ of pulse energy without additional amplification. This laser oscillator operates at a repetition rate of 3.03 MHz and delivers up to 242 W of average output power with a pulse duration of 1.07 ps, resulting in an output peak power of 66 MW. In order to minimize the parasitic nonlinearity of the air inside the laser cavity, the oscillator was operated in a vacuum environment. To start and stabilize soliton mode locking, we used an optimized high-damage threshold, low-loss SESAM. With this new milestone result, we have successfully scaled the pulse energy of ultrafast laser oscillators to a new performance regime and can predict that pulse energies of several hundreds of microjoules will become possible in the near future. Such lasers are interesting for both industrial and scientific applications, for example for precise micromachining and attosecond science. - PublicationMétadonnées seulementExperimentally verified pulse formation model for high-power femtosecond VECSELs(2013)
; ; ; Keller, Ursula - PublicationMétadonnées seulementCutting-edge high-power ultrafast thin disk oscillators(2013)
; - PublicationAccès libreCutting-Edge High-Power Ultrafast Thin Disk Oscillators(2013)
; ; Keller, UrsulaA growing number of applications in science and industry are currently pushing the development of ultrafast laser technologies that enable high average powers. SESAM modelocked thin disk lasers (TDLs) currently achieve higher pulse energies and average powers than any other ultrafast oscillator technology, making them excellent candidates in this goal. Recently, 275 W of average power with a pulse duration of 583 fs were demonstrated, which represents the highest average power so far demonstrated from an ultrafast oscillator. In terms of pulse energy, TDLs reach more than 40 µJ pulses directly from the oscillator. In addition, another major milestone was recently achieved, with the demonstration of a TDL with nearly bandwidth-limited 96-fs long pulses. The progress achieved in terms of pulse duration of such sources enabled the first measurement of the carrier-envelope offset frequency of a modelocked TDL, which is the first key step towards full stabilization of such a source. We will present the key elements that enabled these latest results, as well as an outlook towards the next scaling steps in average power, pulse energy and pulse duration of such sources. These cutting-edge sources will enable exciting new applications, and open the door to further extending the current performance milestones. - PublicationAccès libreExperimentally verified pulse formation model for high-power femtosecond VECSELs(2013)
; ; ; Keller, UrsulaOptically pumped vertical-external-cavity surface-emitting lasers (OP-VECSELs), passively modelocked with a semiconductor saturable absorber mirror (SESAM), have generated the highest average output power from any sub-picosecond semiconductor laser. Many applications, including frequency comb synthesis and coherent supercontinuum generation, require pulses in the sub-300-fs regime. A quantitative understanding of the pulse formation mechanism is required in order to reach this regime while maintaining stable, high-average-power performance. We present a numerical model with which we have obtained excellent quantitative agreement with two recent experiments in the femtosecond regime, and we have been able to correctly predict both the observed pulse duration and the output power for the first time. Our numerical model not only confirms the soliton-like pulse formation in the femtosecond regime, but also allows us to develop several clear guidelines to scale the performance toward shorter pulses and higher average output power. In particular, we show that a key VECSEL design parameter is a high gain saturation fluence. By optimizing this parameter, 200-fs pulses with an average output power of more than 1 W should be possible. - PublicationMétadonnées seulementHigh-power integrated ultrafast semiconductor disk laser: multi-Watt 10 GHz pulse generation(2012)
; ; ; Keller, Ursula - PublicationMétadonnées seulementSESAMs for high-power oscillators: design guidelines and damage thresholds(2012)
; ; Keller, Ursula - PublicationMétadonnées seulementVECSEL gain characterization(2012)
; ; ; Keller, Ursula - PublicationMétadonnées seulementLow repetition rate SESAM modelocked VECSEL using an extendable active multipass-cavity approach(2012)
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