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A. Tarasevitch

Publications and source records attributed to A. Tarasevitch.

7 recordsLinked to original sources
arXiv2024

Table-top soft x-ray source for XAS experiments with photon energies up to 350 eV

We present a table-top setup for femtosecond x-ray absorption spectroscopy based on high harmonic generation (HHG) in noble gases. Using sub-millijoule pump pulses at a central wavelength of 1550 nm broadband HHG in the range 70 to 350 eV was demonstrated. The HHG coherence lengths of several millimeters were achieved by reaching the nonadiabatic regime of harmonic generation. NEXAFS experiments on the boron K edge of a boron foil and a hexagonal BN (hBN) 2D material demonstrate the capabilities of the setup.

physics.optics↗
arXiv2019

Acoustic response of a laser-excited polycrystalline Au-film studied by ultrafast Debye-Scherrer diffraction at a table-top short-pulse X-ray source

The transient acoustic response of a free-standing, polycrystalline thin Au film upon femtosecond optical excitation has been studied by time-resolved Debye-Scherrer X-ray diffraction using ultrashort Cu K$_α$ X-ray pulses from a laser-driven plasma X-ray source. The temporal strain evolution has been determined from the transient shifts of multiple Bragg diffraction peaks. The experimental data are in good agreement with the results of calculations based on the two-temperature model and an acoustic model assuming uni-axial strain propagation in the laser-excited thin film.

cond-mat.mes-hall↗
arXiv2019

Towards attosecond pulse synthesis from solids: spectral shaping, field autocorrelation, and two-color harmonic generation

Harmonic generation from solid surfaces is a promising tool for producing high energy attosecond pulses. We report shaping of the harmonic spectrum to achieve the bandwidth necessary for attosecond pulse generation. The shaping is demonstrated for lower as well as for higher harmonics using single and two-pulse pumping. The measured harmonic field autocorrelation function exhibits attosecond spikes in good agreement with the harmonic spectrum. Double slit experiments reveal a high spatial coherence of the harmonic beam.

physics.plasm-ph↗
arXiv2015

Separation of ultrafast spin currents and spin-flip scattering in Co/Cu(001) driven by femtosecond laser excitation via the complex MOKE

Ultrafast magnetization dynamics in metallic heterostructures consists of a combination of local demagnetization in the ferromagnetic constituent and spin-dependent transport contributions within and in between the constituents. Separation of these local and non-local contributions is essential to obtain microscopic understanding and for potential applications of the underlying microscopic processes. By comparing the ultrafast changes of the polarization rotation and ellipticity in the magneto-optical Kerr effect (MOKE) we observe a time-dependent magnetization profile M(z,t) in Co/Cu(001) films by exploiting the effective depth sensitivity of the method. By analyzing the spatio-temporal correlation of these profiles we find that on time scales before hot electron thermalization (<100 fs) the transient magnetization of Co films is governed by spin-dependent transport effects, while after hot electron thermalization (>200 fs) local spin-flip processes dominate.

cond-mat.mtrl-sci↗
arXiv2014

Efficient Non-Resonant Absorption in Thin Cylindrical Targets: Experimental Evidence for Longitudinal Geometry

Experiments provide a qualitative confirmation of significant absorption of a wide electromagnetic beam propagating along a thin conducting cylinder (the diameter of the cylinder can be orders of magnitude less than the beam waist width). This new physical effect can be used for numerous applications, such as pumping of active media of short-wavelength lasers and creation of low-density channels in the lower atmosphere.

physics.plasm-ph↗