We investigated Terahertz generation in organic crystals DSTMS, DAST and OH1 directly pumped by a Cr:forsterite laser at central wavelength of 1.25 μm.This pump technology provides laser-to-THz energy conversion efficiency higher than 3 percent.Phase-matching is demonstrated over broad 0.1-8 THz frequency range.In our simple setup we achieved hundred μJ pulses tight focus resulting electric magnetic field larger 10 MV/cm Tesla.

Second Harmonic Generation induced by the electric field of a strong nearly single-cycle terahertz pulse with peak amplitude 300 kV/cm is studied in classical inorganic ferroelectric thin film (Ba0.8Sr0.2)TiO3. The dependences SHG intensity on polarization incoming light revealed and interpreted terms plane film. As THz pumps medium range phononic excitations, explained as dynamical change ferrolectric order parameter. It estimated that under action parameter acquires an in-plane component...

We report on the experimental observation of high-power terahertz-radiation-induced damage in a thin aluminum film with thickness less than terahertz skin depth. Damage metal produced by single pulse is observed for first time. The mechanism induced could be attributed to thermal expansion causing debonding from substrate, cracking, and ablation. pattern multiple pulses at fluences below threshold quite different that single-pulse experiments. resembles an array microcracks elongated...

For the first time, data have been obtained on effects of high-intensity terahertz (THz) radiation (with intensity 30 GW/cm 2 , electric field strength 3.5 MV/cm) human skin fibroblasts. A quantitative estimation number histone Н2АХ foci phosphorylation was performed. The per cell studied depending irradiation as well THz pulse energy. performed studies shown that appearance is not related to either oxidative stress (the cells preserve their morphology, cytoskeleton structure, and reactive...

Modification of titanium microstructure after propagation a melting shock wave (SW) generated by femtosecond laser pulse is investigated experimentally and analyzed using hydrodynamic atomistic simulations. Scanning transmission electron microscopy with analysis microdiffraction used to determine the modified subsurface layers titanium. We found that two are beneath surface. A top surface polycrystalline layer nanoscale grains formed from shock-molten material via rapid crystallization. In...

Precisely controlled sequences of ultrashort laser pulses are required in various scientific and engineering applications. We developed a phase-only acousto-optic pulse shaping method for replication TW system. A sequence several Fourier-transform-limited is generated from single femtosecond by means applying piecewise linear phase modulation over the whole emission spectrum. Analysis demonstrates that main factor which limits maximum delay between replicas spectral resolution dispersive...

Abstract The experimental findings on the second harmonic generation (SHG) in centrosymmetric crystal silicon are reported. SHG is induced by extremely high electric field (up to 15 MV/cm) parallel surface of a short terahertz (THz) pulse while probing an infrared femtosecond optical pulse. under such unique conditions reported for first time. At amplitude above 8 MV/cm, quadratic dependence yield integrated over THz duration violated and not changed with further increase field. Saturation...

We demonstrate a simple approach to retrieve the original peak electric field (E-field) strength of high-intensity THz pulses using an electro-optic sampling (EOS) technique and Poynting flux approach. The latter supposes assessment pulse intensity by measurement energy, duration spot size, but its applicability few-cycle needs detailed consideration. applied deconvolution procedure raw EOS data waveform. describe two-step that allows us assess extreme field. First, measurements should be...

The ideal laser source for nonlinear terahertz spectroscopy offers large versatility delivering both ultra-intense broadband single-cycle pulses and user-selectable multi-cycle at narrow linewidths. Here we show a highly versatile platform providing transients with tens of MV/cm peak field as well spectrally pulses, tunable in bandwidth central frequency across 5 octaves several strengths. compact scheme is based on optical rectification organic crystals temporally modulated beam. It allows...

Abstract Enhancement of K α yield from a metal foil covered with rods submicron sizes, low aspect ratio, irradiated by p -polarized femtosecond laser pulses about 10 17 W/cm 2 intensity is demonstrated. Obtained relative increase in X-ray line emission explained model vacuum heating fast electrons.

In this Letter, we investigate the nonlinear effects of extremely intense few-cycle terahertz (THz) pulses (generated from organic crystal 4-NN, NN-dimethylamino-4′4′-N′N′-methyl-stilbazolium 2, 4, 6 trimethylbenzenesulfonate, with peak electrical fields a few MV/cm) on carrier dynamics in n-doped semiconductor thin film In0.53Ga0.47As. By performing open-aperture Z-scan measurements and recording transmitted THz energy through sample, observed strong absorption bleaching effect at high...

A source of terahertz (THz) radiation with a bandwidth 0.5 – 2.5 THz and pulse repetition rate 100 Hz has been developed. The generation is based on optical rectification femtosecond pulses (generated by Cr : forsterite laser system) in nonlinear organic crystal OH1. An scheme multipass amplifier for the system developed to increase energy 2.2 mJ. conversion efficiency pump at wavelength 1.24 μm into found be 2 %. electric field strength 3.5 MV cm−1 attained when focusing beam near...

A versatile table-top high-intense source of terahertz radiation, enabling to generate pulses both broadband and narrowband spectra with a tunable frequency up 3 THz is presented. The radiation are generated by optical rectification femtosecond Cr:forsterite laser setup in nonlinear organic crystal OH1. Electric field strengths were achieved close 20 MV/cm more than 2 MV/cm, correspondingly. Experiments on excitation spin subsystem oscillations an antiferromagnetic NiO carried out. Selective...

We report the experimental results on generating pulsed terahertz (THz) radiation, frequency-tunable within range . The THz pulse generation was implemented using method of optical rectification femtosecond laser pulses in nonlinear organic crystal OH1. frequency tuning radiation provided by adaptive phase – amplitude modulation pump from Cr : forsterite system with a wavelength acoustooptical dispersion delay line.

The results of high-field terahertz transmission experiments on n-doped silicon (carrier concentration $8.7\times10^{16}$ cm$^{-3}$) are presented. We use pulses with electric field strengths up to 3.1 MV cm$^{-1}$ and a pulse duration 700 fs. Huge transmittance enhancement $\sim$90 times is observed increasing the within range 1.5--3.1 cm$^{-1}$.

Abstract The ability to switch ferroics (magnets, ferroelectrics, multiferroics) between two stable bit states is the main principle of modern data storage technology. Due many new ideas, originating from fundamental research during last 50 years, this technology has developed in a breath-taking fashion. Ever increasing demands for faster and more energy efficient strongly motivate studies dynamics triggered by ultrashort stimuli. It been recently realized that nearly single cycle intense...

Extremely intense few-cycle terahertz pulses exhibit complex nonlinear behavior under interaction with $n$-doped opaque Si having low field transmission of $\ensuremath{\sim}0.02%$. Transmission a 700-fs pulse central frequency $\ensuremath{\sim}1.5\phantom{\rule{0.16em}{0ex}}\mathrm{THz}$ through the sample increases up to $\ensuremath{\sim}8%$ for external strength 5 MV/cm and then drops twofold at $\ensuremath{\sim}20\phantom{\rule{0.16em}{0ex}}\mathrm{MV}/\mathrm{cm}$. Electro-optical...

We present the experimental data on direct measurements of spatial distribution terahertz (THz) pulse intensity profile using a commercial silicon-based charge-coupled device (CCD) camera in spectral range from 1-3 THz. A method to measure dimensions high-intensity THz radiation beam focal plane CCD is proposed and experimentally verified.

Abstract K-shell emission from copper target was observed by focusing femtosecond laser pulses very close to the surface-air interface. It shown that mechanism of X-ray is connected with generation fast electrons in air plasma area. Experiments demonstrated moderate intensity radiation ( I L < 10 15 W/cm 2 ) enough produce considerable flux photons at least keV energy. The parameters generated were studied. found after propagation through 40 cm thick layer spectra consisted pronounced K α...

The propagation of light through subwave photonic barriers formed by dielectric nanofilms with the refractive indices changing across films according to specified law n(z) is considered. Generalised Fresnel formulae depending on gradient and profile curvature index describing reflection transmission such inhomogeneous are found. For material thickness, optical properties can change from total producing a technologically controlled n(z). obtained results based exact analytic solutions...

IR femtosecond laser pulses were used for microsurgery of a cell membrane aimed at local and short-duration change in its permeability injection specified extracellular substances into the cells. The possibility noncontact delivery propidium iodide fluorescent dye pEGFP plasmid, encoding green protein, cells with preservation viability was demonstrated.