Berlin 2014 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 40: Interaction with strong or short laser pulses III

A 40.6: Vortrag

Donnerstag, 20. März 2014, 15:15–15:30, BEBEL E34

Strong-field gas excitation and EUV light generation in plasmonic nanostructures — •Murat Sivis, Frederik Busse, and Claus Ropers — IV. Physical Institute, University of Göttingen, Göttingen, Germany

Spatial confinement of electromagnetic fields in tailored plasmonic nanostructures allows for the enhancement of a variety of high-order nonlinear optical phenomena using low-energy laser pulses at MHz repetition rates. Here, we present a detailed study of extreme-ultraviolet (EUV) light generation in noble gases employing bowtie-antennas and tapered hollow waveguides for field-enhancement. In contrast to former expectations [1], we do not observe any signature of coherent high harmonic generation. Instead, we identify atomic and ionic fluorescence induced by multiphoton or strong-fieldgas excitation and ionization as the predominant mechanisms of EUV light generation in such plasmon-assisted scenarios [2,3]. Furthermore, we discuss novel nonlinear effects such as the formation of a waveguide nanoplasma exhibiting a strong bistability, manifest as a pronounced intensity- and pressure-dependent hysteresis in the fluorescence signal. These observations lead to a deeper understanding of nanostructure-enhanced gas excitations and EUV light generation, representing an intriguing link between strong-field physics, plasma dynamics and ultrafast nano-optics.

[1] S. Kim et al., Nature 453, 757 (2008).

[2] M. Sivis et al., Nature 485, E1 (2012).

[3] M. Sivis and C. Ropers, Phys. Rev. Lett. 111, 085001 (2013).