This paper reports on the use of coherent microwave scattering (CMS) for spatially resolved electron number density measurements of elongated plasma structures induced at mid-IR femtosecond filamentation in air. The presented studies comprise one-dimensional mapping of laser filaments induced via 3.9 µm, 127.
View Article and Find Full Text PDFWe describe a new optical diagnostic for determining the composition of gases by measuring the motion of atoms and molecules trapped within very deep optical lattices. This non-resonant method is analogous to conventional Raman scattering, except that the observed spectral features relate to the oscillatory center-of-mass motion of each species within the lattice, determined uniquely by their respective polarizability-to-mass ratio. Depending on the density of the probed sample, detection occurs either via optical scattering at the high end or via non-resonant ionization at the lower end.
View Article and Find Full Text PDFIn this paper we study defocusing and non-paraxial effects associated with nanosecond pulsed laser beam propagation through femtosecond laser generated plasmas. Simulations were performed using a non-reduced wave propagation equation to highlight the role of spatial beam shaping of the nanosecond pulse in improving the laser propagation characteristics. We show that optimizing the shape of the laser intensity profile at the focus using a beam with the ring-liked focus helps to reduce both defocusing and non-paraxial effects.
View Article and Find Full Text PDFBacteria use the type VI secretion system (T6SS) to secrete toxins into pro- and eukaryotic cells via machinery consisting of a contractile sheath and a rigid tube. Rearrangement hotspot (Rhs) proteins represent one of the most common T6SS effectors. The Rhs C-terminal toxin domain displays great functional diversity, while the Rhs core is characterized by YD repeats.
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