Publications

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Highlighted authors are members of the University of Jena.

  2. Polarization-maintaining, rod-type, ytterbium-doped, multi-core fiber for high power operation

    Year of publicationStatusReview pendingPublished in:Optics Express Y. Khalil, C. Jauregui, A. Klenke, M. Bahri, J. Nold, N. Haarlammert, T. Schreiber, J. Limpert
    It has been previously observed that each core in a multi-core fiber has its own birefringence properties. Therefore, obtaining a laser output with a well-defined polarization pattern from a multi-core fiber is challenging. In this work, we explain the origin of this core-dependent birefringence and present a polarization-maintaining, 35-core fiber design that is tested in an oscillator setup, delivering over 100W of power with a polarization contrast ratio close to 10dB. This is a significant improvement with respect to a comparable non-polarization-maintaining multi-core fiber.
    University Bibliography Jena:
    fsu_mods_00030211External link

  3. 117-mJ pulse energy, high average power, Q-switched Yb-doped 49-core fiber amplifier

    Year of publicationStatusReview pendingPublished in:Optics Express M. Bahri, C. Jauregui, A. Klenke, M. Lenski, J. Nold, N. Haarlammert, T. Schreiber, J. Limpert
    This work presents the simultaneous scaling of the average power and pulse energy emitted by multicore fiber laser systems. This is achieved through two series of experiments that use a generation of Yb-doped multicore fiber amplifiers with 49 cores, seeded by a Q-switched multicore fiber laser. One of the main results of these experiments is a total pulse energy of up to 117 mJ at a repetition rate of 5 kHz in quasi-continuous pumping operation. In a different experiment with a smaller core size multicore fiber, an average power of 400 W was achieved at a repetition rate of 5 kHz, corresponding to a pulse energy of 80 mJ in continuous pumping. The experimental results match our simulation predictions, providing valuable insights into the further energy scalability of Yb-doped multicore fibers.
    University Bibliography Jena:
    fsu_mods_00030210External link

  4. Pulse energy scaling of ultrafast lasers via spectral-temporal shaping and coherent combination

    Year of publication L. Stark
    University Bibliography Jena:
    fsu_mods_00019662External link

  7. Precision manufacturing of multicore fibers for superior fiber laser performance

    Year of publicationPublished in:Fiber Lasers XXII: Technology and Systems N. Haarlammert, J. Nold, S. Kuhn, C. Jauregui, J. Limpert, T. Schreiber
    University Bibliography Jena:
    fsu_mods_00024763External link

  8. Influence of core size on the transverse mode instability threshold of fiber amplifiers

    Year of publicationPublished in:Optics Express S. Kholaif, C. Jauregui, J. Nold, N. Haarlammert, S. Kuhn, T. Schreiber, J. Limpert
    We present what we believe to be the first systematic experimental study investigating the impact of core size on transverse mode instability. This is a very complex measurement that requires a significant amount of attention to detail. For example, this study can only be done using fibers which modal characteristics do not change with the core size, a property offered by Ytterbium-doped large-pitch fibers. Additionally, it is mandatory to consider the influence of gain saturation and photodarkening to isolate the impact of the core size on the transverse mode instability threshold. The findings of the measurements reveal that the dependence of this threshold with the core size is weaker than predicted by some theoretical models. Additionally, during the course of these measurements, a mode instability threshold over 600 W was achieved in one of the fibers, which represents the highest, diffraction-limited, average output power reported from an Ytterbium-doped, rod-type fiber so far.
    University Bibliography Jena:
    fsu_mods_00029704External link

  11. Linear field-resolved spectroscopy approaching ultimate detection sensitivity

    Year of publicationPublished in:Optics Express C. Hofer, D. Bausch, L. Fürst, Z. Wei, M. Högner, T. Butler, M. Gebhardt, T. Heuermann, C. Gaida, K. Maiti, M. Huber, E. Fill, J. Limpert, F. Krausz, N. Karpowicz, I. Pupeza
    Electric-field oscillations are now experimentally accessible in the THz-to-PHz frequency range. Their measurement delivers the most comprehensive information content attainable by optical spectroscopy – if performed with high sensitivity. Yet, the trade-off between bandwidth and efficiency associated with the nonlinear mixing necessary for field sampling has so far strongly restricted sensitivity in applications such as field-resolved spectroscopy of molecular vibrations. Here, we demonstrate electric-field sampling of octave-spanning mid-infrared waves in the 18-to-39 THz (600-to-1300 cm−¹) spectral region, with amplitudes ranging from the MV/cm level down to a few mV/cm. We show that employing powerful 2-µm gate pulses is key to approaching the ultimate detection limit of capturing all photons in the temporal gate, as well as providing high linearity with respect to the detected mid-infrared field. This combination of detection sensitivity, dynamic range, and linearity enables the exploitation of the full potential of emerging high-power waveform-controlled infrared sources for (non-)linear spectroscopy of solids, liquids, and gases.
    University Bibliography Jena:
    fsu_mods_00019375External link
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