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A coherent concatenation of multiple Townes solitons may lead to a stable infrared and visible broadband filament in ceramic YAG polycrystal. This self-trapped soliton train helps implement self-referenced multiplex coherent anti-Stokes Raman scattering imaging. Simulations and experiments are presented in this work that help enhance the understanding of the filamentation process and the concatenation of focusing-defocusing cycles in Ceramic and Crystal YAG. Simulations and experiments are presented that examine the dependence of the filamentation onset location and supercontinuum generation upon peak input power. Understanding this dependence is a necessary component of SR-M-CARS implementation.

We study the diffraction of a particular class of beams, composed only by a combination of azimuthally invariant guided modes of an optical fiber. We demonstrate that such beams can be obtained by injecting a Gaussian beam in a small piece of silica graded-index multimode fiber. This minimalistic low-cost method is applied for improving the axial resolution of a two-photon microscope., Comment: 9 pages, 5 figures

We propose an original experimental strategy providing evidence for the first label-free disclosure of muscle actin network based on the nonresonant contribution of a multiplex CARS (M-CARS) microscopy setup. Thin actin filaments are known for being located between thick myosin filaments that can be detected in Second Harmonic Generation (SHG) with our M-CARS setup. The first step of our strategy consists in defining spatial regions where thick myosin filaments or thin actin filaments are expected. Then we present an analysis based on two M-CARS spectra corresponding to these regions, which outcome highlights differences in their relative nonresonant contribution. The final step of the presented strategy is their exploitation on each pixel of the M-CARS hyperspectral image, enabling label-free revelation of thin actin filaments. This qualitative imaging represents a proof of principle for highlighting and discriminating purposes in biological microscopy thanks to a difference in the nonlinear properties of the related proteins. Besides, this peculiar imaging technique results from a competition between several four-wave mixing schemes. This paves the way for considering label-free imaging through a competition involving several light-matter interaction effects, rather than considering several of them singularly., Comment: 12 pages, 5 figures