Hannover 2013 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 34: Ultrashort laser pulses: Applications

Q 34.3: Vortrag

Dienstag, 19. März 2013, 14:30–14:45, F 142

Small-polaron based hologram recording with sub-ps laser pulses in thermally reduced LiNbO₃ — •Holger Badorreck, Stefan Nolte, Pia Baeune, Hauke Bruening, Andreas Buescher, Volker Dieckmann, and Mirco Imlau — School of Physics, Osnabrueck University, Germany

The recording of mixed amplitude and index gratings with fs-laser pulses is studied by means of spatially modulated small polaron densities in single crystals of lithium niobate. Small bound polarons, that appear in the majority of polar oxides, exhibit a tremendous potential for the research field of ultrafast photonics due to their unique optical features. Only recently, the possibility to apply small polarons for highly efficient recording of holograms was successfully demonstrated with single ns-laser pulses in thermally reduced LiNbO₃ (M. Imlau et al., Opt. Express 19, 15322 (2011)). However, the turnover of the widely established results on polaron formation, transport and recombination obtained with cw-light and ns-pulses to dynamic fs-holography has only rarely been addressed in literature. We present our first systematic studies on the recording of mixed holograms with single 100 fs laser pulses in samples with thermal pre-treatment. The results have been corrected for nonlinearities, such as the two photon absorption coefficient and the nonlinear refractive index, that superimpose the diffraction signal. An experimental approach to determine the dispersive features of the recorded holograms in a single measurement, called ultrafast holographic spectroscopy is deduced. Financial support by the DFG (IM 37/5, INST 190/137-1) is gratefully acknowledged.