The pulses at 744 nm with the duration 90 fs, energy 6 mJ and weakly divergent wavefront propagated for more than 100 m and generated a filament followed by unprecedently long high intensity (≥ 1 TW/cm 2 ) light channel. Over a 20 m long sub-section of this channel the pulse energy is transferred continuously to the infrared wing, forming spectral humps that extend up to the wavelength of 850 nm. From 3D+time carrierresolved simulations of 100 m pulse propagation, we show that spectral humps indicate the formation of a train of fs pulses appearing at a predictable position in the propagation path.
New opportunities in ultrasound diagnostics of femtosecond laser filaments with wideband piezoelectric transducers are considered. Transverse spatial resolution better than 100 microns is demonstrated in the single and regular multiple filamentation regime making path toward 3D filament tomography. The simple analytical model of the cylindrical acoustic source fitted well with the experimental data.
We experimentally observed a laser-induced remote high-voltage discharge triggering between two needle electrodes with half-a-cm spacing. The discharge was initiated by a 744-nm, 90-fs, 6-mJ laser pulse undergoing filamentation in air. For the direct voltage below the self-breakdown threshold, triggering of air-gap discharge was synchronized with 10-Hz laser repetition rate and occurred between 40 and 80 m of the propagation path. No discharge guiding was observed. The experimentally registered and simulated remote triggering probability was above 80% in the range of 40-65 m from laser output, and about 50% in the range of 65-80 m. The probability decreases as the postfilament hot spot diverges with simultaneous increase of stochastic laser beam wandering.
We compare transverse structure evolution and energy deposition into the medium within focused multifilament arrays created using two different types of diffraction optical elements (DOEs): TEM11 phase plate and a Dammann grating. We show that the employment of the Dammann grating provides a robust way to create regular multifilament arrays, which is far less dependent on laser beam quality than one using the phase plate.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.