A5106852406- Terahertz technology and applications
- Spectroscopy and Laser Applications
- Laser-Matter Interactions and Applications
- Gyrotron and Vacuum Electronics Research
- Superconducting and THz Device Technology
- Advanced Fiber Laser Technologies
- Advanced Chemical Physics Studies
- High-pressure geophysics and materials
- Molecular Spectroscopy and Structure
- Planetary Science and Exploration
- Plant Pathogens and Resistance
- Spacecraft and Cryogenic Technologies
- Laser-induced spectroscopy and plasma
- Photonic and Optical Devices
- Laser-Plasma Interactions and Diagnostics
- Astro and Planetary Science
CEA DAM Île-de-France
2017-2019
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2017-2019
CEA Cadarache
2017
CEA Grenoble
2017
We study terahertz (THz) emission by two-color femtosecond filaments in air using pump wavelengths ${\ensuremath{\lambda}}_{0}$ from 0.8 to 10.6 $\ensuremath{\mu}\mathrm{m}$. Comprehensive three-dimensional numerical simulations show that tens-of-centimeter long created a 10.6-$\ensuremath{\mu}\mathrm{m}$ pulse can produce mJ energy yields and GV/m field strengths, while the laser-to-THz conversion efficiency exceeds percent level. Changing temperature humidity conditions reveals...
We address the long-standing problem of anomalous growth observed in terahertz (THz) energy yield from air plasmas created by two-color laser pulses, as fundamental wavelength λ0 is increased. Using two distinct optical parametric amplifiers (OPAs), we report THz energies scaling like λ0α with large exponents 5.6≤α≤14.3, which departs λ02 expected photocurrent theory. By means comprehensive 3D simulations, demonstrate that changes beam size, pulse duration, and phase-matching conditions...
Terahertz pulses are very popular because of their numerous applications, for example in security. Located between microwaves and optical waves the electromagnetic spectrum, spectral domain can now be exploited molecular spectroscopy using terahertz emission from plasmas formed by femtosecond laser ionizing gases such as air. Downconversion broadband spectra a plasma produces intense radiation suitable detection suspect materials remotely. The different physical mechanisms involved to create...
We numerically study the influence of chirping and delaying several ionizing two-color light pulses in order to engineer terahertz (THz) wave generation air. By means comprehensive 3D simulations, it is shown that two chirped can increase THz yield when they are separated by a suitable time delay for same laser energy focused propagation geometry. To interpret these results, local current theory revisited we propose an easy, accessible all-optical criterion predicts laser-to-THz conversion...
We theoretically and numerically study the influence of both instantaneous Raman-delayed Kerr nonlinearities as well a long-wavelength pump in terahertz (THz) emissions produced by two-color femtosecond filaments air. Although nonlinearity induced air molecules weakens THz generation, four-wave mixing is found to impact spectra accumulated upon propagation via self-, cross-phase modulations self-steepening. Besides, using local current theory, we show that scaling laser-to-THz conversion...
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not.The documents may come from teaching institutions in France abroad, public private centers.L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de scientifiques niveau recherche, publiés ou non, émanant des établissements d'enseignement recherche français étrangers, laboratoires publics privés.Terahertz emission...
We investigate terahertz emission from two-color femtosecond-laser-induced microplasmas. Under the strongest focusing conditions, microplasmas are shown to act as point sources for broadband terahertz-to-far-infrared radiation, where bandwidth is determined by gas pressure. Semi-analytical modeling allows us identify scaling laws with respect plasma dimensions. find that optical-to-THz conversion efficiency depends crucially on conditions. use this insight demonstrate means of...
The Unidirectional Pulse Propagation Equation (uppe) is often used to compute the forward component of ultrashort light pulses in nonlinear materials. While its accuracy has frequently been reported for many applications ultrafast optics, validity can be questionable ionizing pulses, particular frequency domain below electron plasma . Inaccuracy uppe model this range may detrimental to, e.g., a correct description laser-driven terahertz emission. Here we demonstrate, analytically and...
We studied D + fusion reactions at the CELIA/ECLIPSE laser facility. These were triggered by focusing ECLIPSE (up to 100 mJ on target, pulse duration of 40 fs and focal spot FWHM) a solid C2 D4 target. By detecting 2.5 MeV neutrons, produced in reaction, using C6 D6 scintillators time-of-flight experimental set-up, we measured rate few hundred fusions per shot. At same time, detected also energetic ions keV) diamond detectors. The set-up will be presented results discussed compared with...
Laser filamentation is actively studied for its rich variety of applications, from supercontinuum generation to lightning control [1]. In air, femtosecond filaments result the self-focusing ultrashort light pulses that couple their own plasma channel and stay self-guided upon extended paths at high intensity levels. Driven by strong nonlinearities, these optical structures are able promote broadband THz-to-far-infrared radiation when using laser fields composed two colors, e.g., a...
Over the past decade, increasing potential of terahertz (THz) radiation has stimulated intensive efforts to develop efficient emitters based on ionization gases by ultrashort laser pulses [1]. In order properly calibrate dedicated experiments, nonlinear propagation codes have be particularly accurate describe low-frequency part pulse spectrum. Usually, solving full Maxwell models accounting for multiple processes as well optical and plasma effects is computationally expensive when simulating...
We study THz emission by two-color femtosecond filaments in air using mid-to far-infrared pump wavelengths.3D numerical simulations show that 10.6-µm laser pulses can produce fields with unequaled mJ energies and GV/m amplitudes.
We demonstrate that plasmonic resonances can be used to broaden the terahertz emission spectrum from two-color laser-driven gas-plasmas. This effect controlled by changing polarization properties of elliptically shaped driving laser-pulses.
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Until the nineties, domain of terahertz waves (THz), which extends between 100 GHz and a few tens THz in electromagnetic spectrum, was difficult to access. This situation radically changed with advent time spectroscopy. Terahertz spectroscopy has indeed become an important tool for studying molecules condensed phase. In particular, many chemical, biological, radiological, nuclear explosive agents exhibit characteristic spectral features this frequency region, thus strong potential security...