Abstract In this paper, an ultra-broadband terahertz absorber based on square ring and double H-type of fully dielectric doped silicon is proposed, The absorption efficiency structure numerically verified to exceed 90% across the frequency range 0.978 6.37 THz, with a relative bandwidth 146.76%. It features polarization-independent wide-angle minimal variation within polarization angle 0 90 degrees. TE mode, maintains over up 40° incidence angle, while in TM it achieves 95% 70° angle. energy...

Femtosecond laser pulses with suitable pulse areas are shown to decelerate and stop inside a resonant photonic crystal. The release of the stored fields can be achieved through collision by use an external optical as control field. duty cycle efficiency storage light is much 96%. proposed technique applied real system finite thickness atomic layers.

The Xe(L) system is an amplifier with fundamentally different dynamic characteristics from all previously developed laser amplifiers; it represents the conceptual ideal through full utilization of Kramers–Kronig relations that couple dispersive and absorptive components. response system, optimal governance power compression, rules amplification establishes a minimum gain for amplifier. Accordingly, requires value dispersion to be surpassed; corresponding follows automatically. As leading...

The spectral and spatial characteristics of the Xe(L) amplifier at λ ∼ 2.9 Å determine an optimum for scaling peak power with channel length. Xe31+ Xe32+ (3d → 2p) transition arrays represent two identical optima amplification, a property stemming from extremum components (3245) characteristic their electron configurations. Adroit matching distribution intensity propagating 248 nm pulse dynamically generating self-trapped plasma required to excite selectively efficiently can also...

Cooling of the xenon nozzle flow to T = 230 K produces three leading effects. They are (1) a ∼2.5-fold enhancement Xe(L) hollow atom emission on single-vacancy 3d → 2p charge state arrays, (2) production amplifying self-trapped plasma channels with significantly enhanced lengths and (3) very sharply augmented () double-vacancy transitions in λ ≅ 2.80 Å region.

The triple comparison of (1) single-pulse spectral data, recorded with a CCD-equipped von Hámos spectrometer both axially and transversely; (2) measured time-integrated spectra registered on film (3) x-ray images the morphology self-trapped plasma channel, simultaneously spectra, establishes several leading characteristics saturated amplification observed Xe35+ transition array at λ ≅ 2.86 Å. chief findings are (α) absolute positive correlation formation (β) perfect match amplified...

We report intense (~10 mW), ultra-broadband (~150 THz wide), terahertz-to-infrared, Gaussian-wavefront emission from nanopore-structured metallic thin films under femtosecond laser pulse irradiation. The proposed underlying mechanism is thermal radiation. nanostructures of the metal film are produced by random holes in substrate. Under pulse-train irradiation, we found dramatically enhanced optical absorption, with an absorptivity that was equal to as much 95% surface nanostructure, due both...

Ultrashort light pulses propagating through a resonant photonic crystal can be reshaped to shorter duration output self-induced transparency. The reshaping process is shown result from the unique transmission behavior of structure. Pulse compression and pulse merging, with which multipeak optical evolved give rise single-peak, high-quality transmitted output, are obtained. propagation in compared that bulk atomic medium, shows effect much more powerful former than latter.

Two-color laser mixing in gases can result the emission of broadband, single-cycle terahertz (THz) pulses. In this study, we find that THz wave absorption is observed when and preplasma beam are focused on same point, wavelength influence absorption. The experimental results reveal becomes less pronounced with increasing wavelength. We found decreased sharply at a 1400 nm, which may be related to density, fluorescence profiles were measured using charge-coupled device arrangement prove our...

Single-pulse and time-integrated spectral measurements of the characteristics Xe(L) amplifier at λ ~ 2.8 A indicate an efficiency energy extraction ~30% over a bandwidth ~500 eV. These observations, together with data from prior studies, provide basis for estimating corresponding set scaling limits laboratory sized ~4.5 keV system. Specifically, they are peak power Px 6.0 PW, unfocused intensity Ix 3.4 × 1021 W cm−2, brightness figures to B 4.1 1034 photons s−1 mm−2 mrad−2 (0.1% bandwidth)−1...

We report on the investigation of terahertz-to-infrared (THz-to-IR) thermal emission that relies excitation surface plasmons in metal films deposited a substrate with randomly ordered nanoscale pore arrays. The THz-to-IR radiation was observed both direction laser beam propagation and reverse direction. intensity ratio between backward forward is exponentially dependent nominal thickness porous films. findings are discussed view proposed generation mechanism based propagating plasmon...

The history of power compression is a series developmental epochs that are (1) characteristically marked by technological breakthrough and (2) generally separated factor ∼1010 in density. Based on new advances high‐power coherent x‐ray technology, the transition to nuclear epoch laser interactions presently commencing. Chief outcomes foreseen generation densities 1028–1030 W/cm3 realm, controlled induction interactions, (3) production states forms matter.

The analysis of spatially resolved Xe(L) spectra obtained with Z−λ imaging reveals two prominent findings concerning the characteristics x-ray amplification occurring in self-trapped plasma channels formed by focusing multi-TW subpicosecond 248 nm laser pulses into a high-density gaseous Xe cluster target. They are (1) strongly saturated across both lobes hollow atom 3d → 2p emission profile, breadth that spans spectral width ∼600 eV, and (2) new evidence for formation spatial modes based on...

We conduct a frequency spectrum experiment to investigate terahertz (THz) emissions from laser-induced air plasma under different laser incident powers. The spectra are measured using both air-biased-coherent detection and Michelson interferometer. red-shift of the THz pulse carrier is observed as response increased pump power. These phenomena related collisions can be explained by collision model. Based on these findings, it apparent that tuning achieved through regulation beam.

Terahertz (THz) emission from laser-induced air-plasma is presented.The frequency spectra of THz wave are investigated using an air-biased-coherent-detection method.The measured under different pump-pulse and probe-pulse energies.The become narrow with the increasing pump power we speculate it caused by collision behavior.Meanwhile, bandwidth broadened probe power, which can be explained pulse compression.Based on this finding, optimal spectrum achieved regulating beam.

Terahertz (THz) emission from laser-induced air plasma is a well known and widely used phenomenon. We report that when two laser beams the creating filaments interact with each other, THz absorption observed. believe change in refractive index of causes THz-wave absorption. The following experimental results reveal becomes more pronounced increasing pump power gas species surrounding femtosecond filament can also influence rate.

Anomalous intensity dependent quenching of the Xe(L) hollow atom emission from single Xe <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">33+</sup> (2p̅) and double xmlns:xlink="http://www.w3.org/1999/xlink">34+</sup> (2s̅2p̅) vacancy 3d→2p transition arrays indicates presence a state-selective curve crossing mechanism for field ionization excited 3d xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> configuration by intense (2-3 × 10...

We report on the investigation of bi-directional terahertz-to-infrared (THz-to-IR) radiation from a metal film coated substrate with randomly ordered pore arrays by irradiation femtosecond laser pulses. THz-to-IR was observed both for front-side excitation (laser incident surface) and rear-side substrate). In cases, in propagation direction beam reverse direction. Considering these findings, we propose thermal emission mechanism based production surface plasmons, either delocalized (through...

The high-frequency waves-Terahertz (THz) emission from laser-induced air-plasma is presented. development of high power and efficiency THz wave radiation source has significant value. laser technology led spectroscopic sensing imaging in the region to be widely employed diverse fields such as material characterization, ultrafast dynamic process studies, biological science. waves become one most important areas research. In this research, we develop an time-domain spectroscopy system(THz-...

We report intense (~10 mW), ultra-broadband (~150 THz wide), terahertz-to-infrared, Gaussian-wavefront emission from nanopore-structured metallic thin films under femtosecond laser pulse irradiation. The proposed underlying mechanism is thermal radiation. nanostructures of the metal film are produced by random holes in substrate. Under pulse-train irradiation, we found dramatically enhanced optical absorption, with an absorptivity that was equal to as much 95% surface nanostructure, due both...

THz wave generation in laser-included plasma has attracted considerable attention recently and the intense waves generated from air-induced plasma, serving as broadband source for sensing imaging applications, more researchers' interests recent years. In our experiment, terahertz is detected using Air-Biased Coherent Detection (THz-ABCD) method. This method can achieve third-order nonlinear susceptibility tensor to produce field-induced optical second harmonic photons. THz-ABCD system,...

Terahertz wave generation from air plasma induced by ultrashort laser pulses has been widely studied in the past decade. We report study of terahertz where there is a preformed plasma. found that power generated main pump pulse decreases presence The amount drop increases with generates result confirms key role tunneling ionization mechanism.

Intense Terahertz waves generated from air-induced plasma and serving as broadband THz source provide a promising for innovative technology. generation in selected gases has attracted more researchers' interests recent years. In this research, the emission different atoms is described, such nitrogen, argon helium Michelson. The radiation detected by Golay Cell equipped with 6-mm-diameter diamond-inputting window. It can be seen first time that when pump power lies at stable level, created...