Berlin 2014 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 46: Ultrashort laser pulses II

Q 46.2: Vortrag

Donnerstag, 20. März 2014, 14:15–14:30, DO26 207

Line-by-line pulse shaping for pump-probe spectroscopy applications using a 10 GHz femtosecond frequency comb — •Oliver Kliebisch, Dirk Heinecke, and Thomas Dekorsy — Department of Physics, Universität Konstanz, D-78457 Konstanz

Femtosecond lasers with high repetition rates in the GHz range are becoming more and more important for spectroscopy, especially high speed asynchronous optical sampling (ASOPS). The currently used excitation and detection methods limit the usable resonance frequencies of nanomechanical resonators to the MHz or lower GHz range [1]. Due to the high spacing of the comb lines of a 10 GHz Ti:sapphire laser [2] each mode can be spatially resolved and manipulated individually. A so called GRISM (a combination of a grating and a prism) is used as a dispersive element with nearly constant dispersion [3]. This ensures independent line-by-line modulation over a large bandwidth. The amplitude and phase of each mode can be controlled individually using a spatial light modulator. [4]. This allows to synthesize pulse trains for resonant excitation of acoustic phonons in nanomechanical systems [5]. Using a second 10 GHz Ti:sapphire laser with a detuned repetition rate pump-probe experiments can be carried out employing the method of asynchronous optical sampling [6].

[1] Bruchhausen et al., PRL 106, 077401 (2011). [2] Bartels et al., Opt. Lett. 33, 1905 (2008). [3] Kirchner et al., Opt. Lett., 35, 3264-3266 (2010). [4] Cundiff et al., Nature Photonics 4, 760-766 (2010). [5] Heinecke et al., PRB 87, 075307 (2013). [6] Gebs et al., Opt. Express 18, 5974-5983 (2010).