Hannover 2013 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
Q: Fachverband Quantenoptik und Photonik
Q 63: Photonics IV
Q 63.5: Vortrag
Freitag, 22. März 2013, 15:00–15:15, F 128
Polarization of Random-Lasing Modes under Weak Localization — •Sebastian Knitter, Michael Kues, Michael Haidl, and Carsten Fallnich — Westfälische Wilhelms-Universität Münster
When the diffusive losses induced by strong scattering in a random optical medium are compensated by gain, a recurrent stimulated amplification can arise. The resulting coherent light field is often referred to as “Random-Lasing” (RL) and is associated with narrow peaks atop the regular fluorescence spectrum of the amplifying component [1].
By using a novel single-shot spectro-polarimetric technique [2], we have shown earlier how the emission polarization of weakly scattering organic-dye RL can be manipulated [3] (mean free path lt > 100 µm). Our most recent study however, is concerned with RL modes in the weakly-localized regime (lt of a few µm). Here a static assembly of Zinc oxide nanoparticles was used to provide strong scattering and amplification at the same time.
An excitation of the medium with ps-pulses at 355 nm lead to sharp RL modes, which reproduced very well in spectrum and polarization over more than 2000 pump-laser shots. The exact shape of the emission spectra was characteristic to any given sample position. Also the RL mode-polarization and spectrum were strongly affected by the pump polarization, as expected from FDTD-simulations.
H. Cao et al., Journal of Physics A, 38 (2005)
S. Knitter et al., Opt. Lett., 36, 16 (2011)
S. Knitter et al., Opt. Lett., 37, 17 (2012)