Bonn 2025 – wissenschaftliches Programm
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K: Fachverband Kurzzeit- und angewandte Laserphysik
K 3: Light and Radiation Sources I
K 3.5: Vortrag
Montag, 10. März 2025, 18:15–18:30, HS XI ITW
Resonantly Enhanced Frequency Conversion at High Intensities towards the Vacuum Ultraviolet — •Marietta Coelle, Oskar Ernst, and Thomas Halfmann — Technische Universität Darmstadt
Vacuum Ultraviolet (VUV) light is of big interest for a variety of applications like lithography, attosecond physics or spectroscopy. One approach to generate coherent VUV is the nonlinear frequency up-conversion of visible light provided by pulsed laser sources in noble gases. Due to low particle densities and higher order nonlinearity, the conversion efficiencies are generally small. This can be counteracted by increasing the laser intensity as well as by increasing the nonlinear susceptibility when using multi-photon resonances. However, high-power laser systems mostly have a fixed wavelength why it is difficult to find suitable resonances. At intensities above TW/cm2, additionally, AC stark shifts alter the atomic level structure significantly. We present a way to make use of these shifts. Coupling an additional control transition gives rise to large, intensity-dependent Autler-Townes splittings and by adjusting the control laser intensity, the resonance of the atom can then be shifted towards the frequency of an initially off-resonant multi-photon transition. Specifically, we present a coupling scheme in xenon which only uses one single, fixed-frequency laser, paving the way to efficiently generate VUV light of 100 to 130 nm with compact, fixed-frequency, high-power laser systems.
Keywords: nonlinear optics; picosecond pulses; dressed states; spectroscopy; high-power laser