Engineering topics
Blaga, Cosmin I.
Publications and source records attributed to Blaga, Cosmin I..
High-power few-cycle Cr:ZnSe mid-infrared source for attosecond soft x-ray physics
The development of mid-infrared, high-energy pulses of extremely short pulse duration is of great importance to the strong-field physics community, as it enables extension of the high-harmonic cutoff towards the keV range of photon energies. Here we demonstrate a C r 2 + : Z n S e laser amplifier delivering 7 mJ, 100 fs pulses at 1 kHz repetition rate and 2.4 µm central wavelength with excellent energy stability and beam quality. These pulses are post-compressed to 39 fs, 6.2 mJ, and 115 GW peak power in a novel nonlinear compression scheme. The laser system was used to generate coherent soft x-ray radiation up to 0.6 keV covering the entire water window, which is of high importance for bio-relevant applications. The obtained results open a wide range of applications in nonlinear optics, attosecond and strong-field physics, and remote sensing.
Diffractive Imaging of C 60 Structural Deformations Induced by Intense Femtosecond Midinfrared Laser Fields
Theoretical studies indicated that C 60 exposed to linearly polarized intense infrared pulses undergoes periodic cage structural distortions with typical periods around 100 fs (1 fs = 10 –15 s). Here, we use the laser-driven self-imaging electron diffraction technique, previously developed for atoms and small molecules, to measure laser-induced deformation of C 60 in an intense 3.6 μm laser field. A prolate molecular elongation along the laser polarization axis is determined to be (6.1 ± 1.4)% via both angular- and energy-resolved measurements of electrons that are released, driven back, and diffracted from the molecule within the same laser field. The observed deformation is confirmed by density functional theory simulations of nuclear dynamics on time-dependent adiabatic states and indicates a nonadiabatic excitation of the h g (1) prolate-oblate mode. Here, the results demonstrate the applicability of laser-driven electron diffraction methods for studying macromolecular structural dynamics in four dimensions with atomic time and spatial resolutions.
Tunable mid-infrared source of light carrying orbital angular momentum in the femtosecond regime
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