Osterhoff, J.; Popp, A.; Major, Zs.; Marx, B.; Rowlands-Ree, T.P.; Fuchs, Matthias; Geissler, M.; Horlein, R.; Hidding, B.; Becker, S.; Peralta, E.A.; Schramm, U.; Gruner, F.; Habs, D.; Krausz, F.; Hooker, Simon M.; and Karsh, Stefan, "Generation of Stable, LowDivergence Electron Beams by Laser-Wakefield Acceleration in a Steady-State-Flow Gas Cell" (2008). Matthias Fuchs Publications. 4.

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In femtosecond stimulated Raman microscopy (FSRM) a spectrally broad pulse (Raman probe) and a spectrally narrow pulse (Raman pump) interact in a sample and thereby generate a Raman spectrum of the focal volume. Here a novel light source for FSRM is presented. It consists of an 8-fs laser (repetition rate of 75 MHz) operating as Raman probe. A Yb(3+) based fiber amplifier generates the Raman pump light at 980 nm. The amplifier is seeded by the spectral wing of the 8-fs laser output which ensures synchronisation of pump and probe pulses. Spectral and temporal characteristics of these pulses are reported and simultaneous recording of broadband Raman spectra relying on these pulses is demonstrated.

Femtosecond stimulated Raman microscopy (FSRM) is an upcoming technique in nonlinear microscopy which facilitates rapid chemical mapping. It employs femtosecond white-light pulses as probe pulses and intense picosecond pulses as pump pulses. Stimulated Raman scattering (SRS) occurs at the focus of a scanning microscope. Chemical constituents in the sample are identified via their Raman signatures. In this article, disturbing interference patterns in FSRM are reported. They are caused by a broadening of the pump pulse due to nonlinear interactions in the focal region of the microscope and reduce the signal-to-noise ratio. The properties of these modulations are explored, and the methods to suppress them are presented.