The mechanism of laser-driven relativistic pair-jet production qualitatively changes as laser intensity exceeds $I\gtrsim5\times10^{22}$ W/cm$^{2}$ because of the appearance of laser-induced strong-field QED processes. Here, we show that by exceeding this intensity additional physics operates and opens a new and efficient channel to convert laser photons into dense pair-jets -- the combination of nonlinear Compton scattering and the Bethe-Heitler process. This channel generates relativistic electron-positron jets more than three orders of magnitude denser than has so far been possible. We find that the process is so efficient that it leads to the prolific production of heavier pairs as well. The jets produced by this new channel will enable the study of collective processes in relativistic electron-positron plasmas.
It is shown that when relativistically intense ultrashort laser pulses are reflected from the boundary of a plasma with a near-critical density, Doppler frequency shift leads to generation of intense radiation both in the high-frequency, up to the X-ray, range, and in the low-frequency, mid-infrared, range. The efficiency of energy conversion into the wavelength range of greater than 3 $μ$m can reach several percent, which makes it possible to obtain relativistically intense pulses in the mid-infrared range. These pulses are synchronized with high harmonics in the ultraviolet and X-ray ranges,…
We present a novel scheme to obtain robust, narrowband, and tunable THz emission by using a nano-dimensional overdense plasma target that is irradiated by two counter-propagating detuned laser pulses. So far, no narrowband THz sources with a field strength of GV/m-level have been reported from laser-solid interaction. We report intense THz pulses at beat-frequency ($\simeq$30THz) generated due to strong plasma current produced by the beat ponderomotive force in the colliding region, with an unprecedentedly high peak field strength of 11.9GV/m and spectral width $(Δf/f$$\simeq$$5.3\%)$ from 2D …
Strong electromagnetic pulses (EMP) are generated from intense laser interactions with solid-density targets, and can be guided by the target geometry, specifically through conductive connections to the ground. We present an experimental characterization, by time- and spatial-resolved proton deflectometry, of guided electromagnetic discharge pulses along wires including a coil, driven by 0.5 ps, 50 J, 1e19 W/cm2 laser pulses. Proton-deflectometry data allows to time-resolve first the EMP due to the laser-driven target charging and then the return EMP from the ground through the conductive targ…
High-resolution measurements of the spatial and temporal evolution of megagauss magnetic fields created in intense short-pulse laser-plasma interactions
Sources of intense, ultra-short electromagnetic pulses enable applications such as attosecond pulse generation, control of electron motion in solids and the observation of reaction dynamics at the electronic level. For such applications both high-intensity and carrier envelope phase~(CEP) tunability are beneficial, yet hard to obtain with current methods. In this work we present a new scheme for generation of isolated CEP-tunable intense sub-cycle pulses with central frequencies that range from the midinfrared to the ultraviolet. It utilizes an intense laser pulse which drives a wake in a plas…
Ionization is a fundamental process in intense laser-matter interactions, and is known to cause plasma defocusing and intensity clamping. Here, we investigate theoretically the propagation dynamics of an intense laser pulse in a helium gas jet in the ionization saturation regime, and we find that the pulse undergoes self-focusing and self-compression through ionization-induced reshaping, resulting in a manyfold increase in the laser intensity. This unconventional behavior is associated with the spatiotemporal frequency variation mediated by ionization and spatiotempral coupling. Our results il…
Generation of terahertz radiation by an oscillating discharge, excited with short laser pulses, may be controlled by geometry of the irradiated target. In this work, an annular target with a thin slit is considered as an efficient emitter of secondary radiation when driven by a short intense laser pulse. Under the irradiation, a slit works as a diode, which is quickly filled by dense plasma, closing the circuit for a travelling discharge pulse. Such a diode defines the discharge pulse propagation direction in a closed contour, enabling its multiple passes along the coil.The obtained oscillatin…
We show theoretically that an intense femtosecond optical pulse incident normally on a metal surface tends to decay into a pair of counter-propagating surface plasmon-polaritons (SPPs). The interference field heats the medium periodically, which causes a periodic permittivity perturbation and resonantly amplifies the magnitudes of SPPs. The instability growth time is only 10-50 fs for typical metals at damaging laser fluences. This mechanism is promising for the interpretation of laser-induced periodic surface structures formation in a single-pulse pumping regime.
Harmonic emission from cluster nanoplasmas subject to intense short laser pulses
研究了短脉冲强红外激光作用下团簇纳米等离子体的谐波辐射。在以前的出版物[M。Kundu等人，Phys. Rev. A 76，033201（2007）]，我们报道了粒子单元模拟结果，其显示当电离和膨胀团簇的Mie等离子体频率与相应的谐波频率共振时，低阶谐波的共振增强。同时，我们发现，高次谐波几乎不存在于光谱中，即使在高强度。目前的文件是集中在分析建模的过程中。我们发现，由于非线性共振的动力学随机性抑制高次谐波的发射。
A scheme for generating intense high-harmonic optical vortices is proposed. It relies on spin-orbit interaction of light when a relativistically-strong circularly polarized laser pulse irradiates a micro-plasma-waveguide. The intense laser field drives a strong surface wave at the inner boundary of the waveguide, which leads to high-order harmonic generation as the laser traveling inside. For a circularly polarized drive laser, the optical chirality is imprinted to the surface wave, which facilitates conversion of spin angular momentum of the fundamental light into orbital angular momenta of t…
