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    Oriented zinc oxide nanorods: A novel saturable absorber for lasers in the near-infrared
    (Frankfurt, M. : Beilstein-Institut zur Förderung der Chemischen Wissenschaften, 2018-10-23) Loiko, Pavel; Bora, Tanujjal; Serres, Josep Maria; Yu, Haohai; Aguiló, Magdalena; Díaz, Francesc; Griebner, Uwe; Petrov, Valentin; Mateos, Xavier; Dutta, Joydeep
    Zinc oxide (ZnO) nanorods (NRs) oriented along the crystallographic [001] axis are grown by the hydrothermal method on glass substrates. The ZnO NRs exhibit a broadband (1–2 µm) near-IR absorption ascribed to the singly charged zinc vacancy VZn−1. The saturable absorption of the ZnO NRs is studied at ≈1 µm under picosecond excitation, revealing a low saturation intensity, ≈10 kW/cm2, and high fraction of the saturable losses. The ZnO NRs are applied as saturable absorbers in diode-pumped Yb (≈1.03 µm) and Tm (≈1.94 µm) lasers generating nanosecond pulses. The ZnO NRs grown on various optical surfaces are promising broadband saturable absorbers for nanosecond near-IR lasers in bulk and waveguide geometries.
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    Experimental investigations on the suppression of Q-switching in monolithic 40 GHz mode-locked semiconductor lasers
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2006) Hüttl, Bernd
    Inherent Q-switching as a source of intra-cavity pulse energy modulations, i.e. unwanted amplitude noise, is still a challenging task in order to fabricate monolithic mode-locked semiconductor lasers in view of different commercial applications. In this paper, the results of experimental investigations on the influence of the quantum well number on the occurrence and suppression of Q-switching in 40 GHz mode-locked multiple quantum well buried heterostructure lasers are presented. Improved mode-locked lasers emit short optical pulses (<=1.6 ps) with very low amplitude noise (1-2%) and timing jitter (50-100 fs).
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    Dynamics of an inhomogeneously broadened passively mode-locked laser
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2018) Pimenov, Alexander; Vladimirov, Andrei G.
    We study theoretically the effect of inhomogeneous broadening of the gain and absorption lines on the dynamics of a passively mode-locked laser. We demonstrate numerically using travelling wave equations the formation of a Lamb-dip instability and suppression of Q-switching in a laser with large inhomogeneous broadening. We derive simplified delay-differential equation model for a mode-locked laser with inhomogeneously broadened gain and absorption lines and perform numerical bifurcation analysis of this model.