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217 results on '"Zellmer, H."'

14. The renaissance and bright future of fibre lasers

Author

Tünnermann, A., Schreiber, T., Röser, F., Liem, A., Höfer, S., Zellmer, H., Nolte, S., Limpert, J., and Publica

Subjects
fiber laser, stimulated emission, optical wavelength, renaissance, diffraction, doping additives, solid state laser, photonic crystal, crystal, solid state material
Abstract

The first rare-earth-doped fibre lasers were operated in the early 1960s and produced a few milliwatts at a wavelength around 1 µm. For the next several decades, fibre lasers were little more than a low-power laboratory curiosity. Recently, however, fibre lasers have entered the realm of kilowatt powers with diffraction-limited beam quality. In this paper we review the reasons for this power evolution. Beyond this, we will discuss how the next generation of fibres, so-called photonic crystal fibres, enable upward power scaling and therefore open up the avenue to new performance levels of solid-state lasers.

Published
2005

15. Scaling single-mode photonic crystal fiber lasers to kilowatts

Author

Limpert, J., Liem, A., Schreiber, T., Röser, F., Zellmer, H., Tünnermann, A., and Publica

Abstract

Photonic crystal fiber lasers have the potential to revolutionize-earth-doped fiber lasers in high-power operation. The first rare-earth-doped fiber lasers, which produced a few milliwatts at a wavelength of around 1 µm, were operated in the early 1960s. For the next several decades, fiber lasers were little more than a low-power laboratory curiosity. Recently, however, with the advent of reliable, high-brightness, diode-pumped lasers and of double-clad fibers to facilitate coupling the pump light into the fiber they are entering the realm of kilowatt powers with diffraction-limited beam quality Compared with bulk solid-state lasers, the chief advantage of fiber lasers is their outstanding heat-dissipation capability, which is due to the large ratio of surface to volume of such a long, thin gain medium. As a result, thermal distortion of the beam is negligible, and the beam quality depends solely on the physical design of the fiber. Fiber lasers and amplifiers have a very high single-pass gain; therefore, low laser thres holds can be efficiently pumped with diode lasers. Moreover, the broad gain band width, and the compactness, robustness and simplicity of operation make fiber lasers attractive for a host of applications.

Published
2004

16. Kurzpulsfaserlaser: Neue Quellen für die Präzisions-Materialbearbeitung

Author

Zellmer, H., Nolte, S., Tünnermann, A., and Publica

Abstract

Die Lasermaterialbearbeitung mit Femtosekundenpulsen erlaubt die präzise Strukturierung von metallischen und nichtmetallischen Werkstoffen ohne den Einfluss störender, thermischer Effekte. Die geringe kommerzielle Verfügbarkeit von Kurzpulslasersystemen mit hoher mittlerer Leistung hat jedoch bisher eine Überführung dieser Technologie von den Forschungslaboren in die industrielle Anwendung verhindert. Hier bietet der Faserlaser eine einfache Möglichkeit, kompakte anwendungstaugliche Kurzpulsquellen mit hoher Pulsenergie und mittlerer Leistung zu realisieren.

Published
2004

17. 500 W continuous-wave fiber laser with excellent beam quality

Author

Limpert, J., Liem, A., Zellmer, H., Tünnermann, A., and Publica

Abstract

Power scaling of continuous-wave fibre lasers with up to 0.5 kW output powers from a single fibre with nearly diffraction-limited beam quality without the limitation of nonlinear effects is reported.

Published
2003

18. Performance comparison of rear impact dummies Hybrid III (TRID), BioRID and RID2

Author

Philippens, M.M.G.M., Zellmer, H., Muser, M., Stamm, M., Walz, F., Hell, W., Langwieder, K., and TNO Wegtransportmiddelen

Subjects
Rear impact, Traffic, Car seats, Dummies, Head restraint
Abstract

The objective of this study is to compare the performance of different seats using the named three dummies in low speed rear-end impact sled tests.

Published
2002

19. External design freedom for optimalization of resonator originated beam shaping

Author

Zeitner, U.D., Wyrowski, F., Zellmer, H., and Publica

Subjects
Laser resonator, diffractive optics, laser beam shaping, laser modes
Abstract

Modern fabrication techniques like electron beam lithography allow the use of resonator mirrors with sophisticated surface modulation. We use this flexibility to realize a resonator with a beam the intensity distribution of which is specified in the focal region. The phase in focal region is used as freedom to homogenize the beam in the active medium and by that to allow the satisfaction of the laser gain condition. This is possible by a decoupling of the beam propagation characteristic of the beam inside and outside of the cavity. The design concept is described and experimentally demonstrated in Nd:YAG laser.

Published
2000

26. Rod-type fiber laser

Author

Deguil-Robin, N., primary, Limpert, J., additional, Manek-Hönninger, I., additional, Salin, F., additional, Röser, F., additional, Liem, A., additional, Schreiber, T., additional, Nolte, S., additional, Zellmer, H., additional, Tünnermann, A., additional, Broeng, J., additional, Petersson, A., additional, and Jakobsen, C., additional

Published
2005
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28. High-power rod-type photonic crystal fiber laser

Author

Limpert, J., primary, Deguil-Robin, N., additional, Manek-H�nninger, I., additional, Salin, F., additional, R�ser, F., additional, Liem, A., additional, Schreiber, T., additional, Nolte, S., additional, Zellmer, H., additional, T�nnermann, A., additional, Broeng, J., additional, Petersson, A., additional, and Jakobsen, C., additional

Published
2005
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29. 120-W short-length rod-type photonic crystal fiber laser

Author

Limpert, J., primary, Deguil-Robin, N., additional, Manek-Honninger, I., additional, Salin, F., additional, Roser, F., additional, Liem, A., additional, Schreiber, T., additional, Nolte, S., additional, Zellmer, H., additional, Tunnermann, A., additional, Broeng, J., additional, Petersson, A., additional, and Jakobson, C., additional

Published
2005
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31. High power picosecond fiber amplifier based on spectral compression

Author

Limpert, J., primary, Deguil-Robin, N., additional, Manek-Hönninger, I., additional, Salin, F., additional, Schreiber, T., additional, Liem, A., additional, Röser, F., additional, Zellmer, H., additional, Tünnermann, A., additional, Courjaud, A., additional, Hönninger, C., additional, and Mottay, E., additional

Published
2005
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