Speaker
Jan Reislöhner
(Institute of Optics and Quantum Electronics, FSU Jena)
Description
Pulses with durations short enough to probe the electronic timescale can be generated in the XUV and in the IR-VIS regime. At photon energies around 4-20 eV, pulses with such extremely short durations have not yet been demonstrated. Frequency conversion in a gas cell or filamentation yields comparatively short pulses, but the complex interplay of nonlinear light-matter interaction and significant linear dispersion has prevented to approach the femtosecond barrier, even when extremely short (<4 fs) driving pulses are used. For spectroscopic applications such as transient absorption spectroscopy, broadband and sub-femtosecond pulses in the deep-UV would be very useful, because they allow the direct probing of the bandgap in many materials.
Laser pulses (centre wavelength 700 nm, pulse duration 5 fs) are focused into a generation medium (sapphire, MgO, fused silica, BK7 glass) with a beam waist of 85 μm and a crossing angle 2α = 1°. A spectrometer has been constructed with resolution in the emission angle φ behind the generation medium. Data stacks dependent on 3 parameters (wavelength λ, pulse delay τ, emission angle φ) are recorded.
The cascaded processes of third harmonic generation (THG) and self-diffraction yield a multifaceted emission pattern in the deep-UV with pulse durations < 3 fs at selected emission angles. Hence it is demonstrated that the generation of short deep-UV pulses by THG can be improved by using a noncollinear geometry.
Primary authors
Adrian Pfeiffer
(Institute of Optics and Quantum Electronics, FSU Jena)
Christoph Leithold
(Institute of Optics and Quantum Electronics, FSU Jena)
Jan Reislöhner
(Institute of Optics and Quantum Electronics, FSU Jena)
Jesus Delgado Aguillon
(Institute of Optics and Quantum Electronics, FSU Jena)
