Modern electronics are founded on switching the electrical signal by radio frequency electromagnetic fields nanosecond time scale, limiting information processing to gigahertz speed. Recently, optical switches have been demonstrated using terahertz and ultrafast laser pulses control enhance speed picosecond a few hundred femtoseconds scale. Here, we exploit reflectivity modulation of fused silica dielectric system in strong light field demonstrate (ON/OFF) with attosecond resolution....

Abstract During 30 September to 9 October 2016, Hurricane Matthew traversed the Caribbean Sea east coast of United States. its period greatest intensity, in central Caribbean, excited a large number concentric gravity waves (GWs or CGWs). In this paper, we report on hurricane‐generated CGWs observed both stratosphere and mesosphere from spaceborne satellites ionosphere by ground Global Positioning System receivers. We found with horizontal wavelengths ~200–300 km (height ~30–40 km) airglow...

The chirped pulse amplification technique has enabled the generation of pulses a few femtosecond duration with peak powers multi-Tera and Peta-Watt in near infrared. Its implementation to realize even shorter duration, higher energy, repetition rate laser systems relies on overcoming limitations imposed by damage critical components. In particular, coatings amplifiers post-compression optics have become bottleneck. robustness optical is typically evaluated numerically through steady-state...

Abstract Femtosecond-laser-assisted material restructuring employs extreme optical intensities to localize the ablation regions. To overcome minimum feature size limit set by wave nature of photons, there is a need for new approaches tailored processing at nanoscale. Here, we report formation deeply-subwavelength features in silicon, enabled localized laser-induced phase explosions prefabricated silicon resonators. Using short trains mid-infrared laser pulses, demonstrate controllable high...

We present a fully three-dimensional kinetic framework for modeling intense short pulse lasers interacting with dielectric materials. Our work modifies the open-source Particle-In-Cell (PIC) code EPOCH to include new models molecular photoionization and optical response. use this model laser-induced damage of materials by few-cycle laser pulses. The is benchmarked against experimental results bulk silica targets then applied multi-layer mirrors sequence simulations varying fluence. This...

Abstract Conventional absorbing, reflective and scattering polarizers are facing various issues, such as severe optical loss, necessary oblique incidence, humidity sensitivity or aging‐caused failure. Subnanowires (SNWs) with polymer‐analogue properties, intrinsic order, multi‐level interactions attract widespread attention superior candidates for building blocks of polarizers. Herein, freestanding flexible liquid crystal (LC)‐SNW films prepared through a facile directional coating method,...

We present and investigate a hybrid laser-based method of surface shaping for damage mitigation on fused silica surfaces. Damage sites were removed precisely shaped into an optically-benign cone by procedure femtosecond laser ablation with subsequent CO2 polishing process. The morphology the rim was quantitatively predicted numerical model. Since heat-affected zone (HAZ) process effectively confined optimization parameters, dimensions raised reduced order magnitude. intensity on-axis hotspot...

This study investigates the recovery of oily sludge using ultrasound-assisted rhamnolipids and uses oil yield as an evaluation index. The Box–Behnken response surface method was employed to investigate individual interactive effects four different operating factors: frequency, dosage, liquid–solid ratio, stirring speed. model optimization results showed that order degree influence these factors is frequency > ratio dosage mathematical predicted highest 92.27%, which highly accurate (in 95%...

High peak and average power lasers with high wall-plug efficiency, like the Big Aperture Thulium (BAT) laser, have garnered tremendous attention in laser technology. To meet requirements of BAT we developed low-dispersion reflection multilayer dielectric (MLD) gratings suitable for compression high-energy pulses operations at 2 micron wavelength. We carried out 10000-on-1 damage tests to investigate fluence thresholds designed MLD mirrors, which were found between 100-230 mJ/cm2. An...

Abstract Inorganic single crystals with anisotropic structures usually suffer from high brittleness and stiffness. Flexible polymers are used to replace inorganic crystals, but the hot‐stretching‐induced orientation process is tedious, oriented molecular chains tend revert random coils during aging. To overcome these obstacles using similarities between sub‐1 nm nanowires (NWs) linear polymers, we successfully fabricated anisotropic, transparent, flexible, stable (ATFS) NW films great...

In order to suppress the frequency modulation amplitude (FM-to-AM) conversion induced by a Nd:glass regenerative laser amplifier, birefringent quartz crystal was designed theoretical simulation and inserted into amplifier. A broadband amplifier with flattop region of ∼3.7 nm in gain spectrum developed. An all-fiber front-end system used generate 2 ns shaped pulse spectral width ∼0.5 nm, which broadened two-stage phase modulator. Then, amplified spectral-broadened The output temporal waveform...

This study is the first to use a response surface method optimize main parameters of ultrasonic-assisted recovery oil from oily sludge. The solvent with highest (xylene) and most suitable process (Ultrasonic Assisted Extraction) were selected based on rate. Then, single-factor experiments performed determine best parameter range sludge ratio, frequency, duration, temperature. Box-Behnken methodology was used influence each variable recovery. Solvent duration found have significant effects....

The distributed SLAM system has a similar estimation performance and requires only one-fifth of the computation time compared with centralized particle filter. However, impoverishment is inevitably because random particles prediction resampling applied in generic filter, especially problem that involves large number dimensions. In this paper, filter use was improved two aspects. First, we important function local filters adaptive values were used to replace set constants computational...

Optical smoothing is a very effective method to restrict mid-to-high spatial frequency errors generated by computer-controlled sub-aperture polishing technologies. According Preston's equation, pressure distribution the key factor in describing effect of tool. Although classic bridging model can solve during process, it only suitable for tool that consists rigid base, compliant interlayer, thin metal plate, and pitch layer. In this paper, mathematical applicable any multi-layer proposed,...

Both gallium oxide and nitride have great potential for use as high power transparent conducting materials a wide range of optoelectronic applications. It is, therefore, important to determine the dynamic optical field breakdown these materials. Here, we report laser damage thresholds Ga2O3 GaN using 9 fs few-cycle pulses with center wavelength near 760 nm. We laser-induced (LIDTs) both single pulse multi-pulse exposures, LIDT showing significant reduction compared (in some cases,...

Multilayer dielectric (MLD) gratings with high diffraction efficiency and a laser-induced damage (LID) threshold for pulse compressors are key to scaling the peak average power of chirped amplification lasers. However, surface defects introduced by manufacturing, storage, handling processes can reduce LID resistance MLD impact laser output. The underlying mechanisms such defect-initiated remain unclear, especially in femtosecond regime. In this Letter, we model dynamic interactions 20-fs...

Holography has been widely applied in fields of imaging and measurement, but the optical setup traditional phase-shifting holography is complicated. Here, a kind radial-shearing with Greek-ladder zone plates presented, which largely simplifies configuration for holographic recording enhances stability system. A 1951 U.S. Air Force resolution test target measured by experiment to verify validity our proposed method. Benefiting from amplitude-only diffractive lenses high common path,...

The interaction of ultrafast laser pulses and dielectric materials has been under intensive research for improvement induced damage optics high intensity lasers. A 2D model based on Keldysh photoionization finite-different time-domain (FDTD) algorithm are used to simulate the ionization processes in multilayer interference coatings, taking nonlinear photoionization, impact ionization, plasma collision into account. Simulation experimental results bulk fused silica with different pulse...

Abstract In this letter, a triple‐band filtering power divider (FPD) is proposed for passive circuit implementation with good isolation. The FPD composed of coupled microstrip lines by applying comprehensive design method. Based on the method and developed topology, employed resonators, input/output feedlines as well isolated resistor are properly arranged to achieve desired isolation response. To validate our concept method, operating at 2.3–2.33, 2.39–2.42, 2.5–2.53 GHz implemented return...