Optical orientation of spin-polarized heavy and light holes followed by relaxation to other valence subband states has been observed unambiguously in undoped bulk GaAs spite the extremely short spin time. The measured time for is 110 fs $\ifmmode\pm\else\textpm\fi{}10%$. results are relevant applications such as interpretation transport semiconductors well assessment feasibility hole-based spin-transport devices which relies on precise knowledge hole-spin

We use optical-pump terahertz-probe spectroscopy to investigate the near-threshold behavior of photoinduced insulator-to-metal (IM) transition in vanadium dioxide thin films. Upon approaching ${T}_{c}$ a reduction fluence required drive IM is observed, consistent with softening insulating state due an increasing metallic volume fraction (below percolation limit). This phase coexistence facilitates growth homogeneous conducting following superheating via photoexcitation. A simple dynamic...

We describe a film of highly-aligned single-walled carbon nanotubes that acts as an excellent terahertz linear polarizer. There is virtually no attenuation (strong absorption) when the polarization perpendicular (parallel) to nanotube axis. From data we calculated reduced dichrosim be 3, corresponding nematic order parameter 1, which demonstrates nearly perfect alignment well intrinsically anisotropic response in film.

We systematically investigate the excitonic dephasing of three representative transition-metal dichalcogenides, namely, ${\mathrm{MoS}}_{2}$, ${\mathrm{MoSe}}_{2}$, and ${\mathrm{WSe}}_{2}$ atomic monolayer thick bulk crystals, in order to gain a proper understanding factors that determine optical coherence these materials. Coherent nonlinear spectroscopy temperature dependent absorption, combined with theoretical calculations phonon spectra, indicate electron-phonon interactions, be...

Ultrafast photoinduced phase transitions could revolutionize data-storage and telecommunications technologies by modulating signals in integrated nanocircuits at terahertz speeds. In quantum phase-changing materials (PCMs), microscopic charge, lattice, orbital degrees of freedom interact cooperatively to modify macroscopic electrical optical properties. Although these interactions are well documented for bulk single crystals thin films, little is known about the ultrafast dynamics...

We observe terahertz emission by optical rectification of an intense 1.5-eV, 50-fs pulse in single-crystal iron thin films grown molecular beam epitaxy. The azimuthal dependence the indicates presence a magnetic nonlinearity and nonmagnetic surface nonlinearity.

The authors have grown (Al,Ga)As/GaAs two-dimensional electron gas (2DEG) structures with lightly doped regions of (Al,Ga)As and superlattices in the undoped GaAs. Using this technique, they obtained ultralow density (2*1010 cm-2), high-mobility samples where phonon scattering at 4 K is dominant factor limiting mobility; reducing measurement temperature to below 1.5 gives mobilities up 107 cm2 V-1 s-1.

Abstract This study was designed to evaluate safety and effectiveness of the 0.9 mm excimer laser coronary catheter with increased parameters. We report a prospective trial 100 calcified and/or balloon‐resistant lesions where new used at standard or higher energy level facilitate angioplasty. Standard in‐hospital clinical angiographic parameters were collected measured. Laser technical success obtained in 87 (92%), procedural reached 88 (93%), 82 (86%). Increased for 29 resistant lesions....

Abstract Background Paclitaxel‐eluting stents inhibit restenosis; however, this technology has drawbacks (e.g., stent thrombosis, requirement for long‐term antiplatelet ther‐ apy, and cost—particularly patients with multivessel disease). Systemic treatment a novel 130‐nm, albumin‐bound particle form of paclitaxel ( nab ‐paclitaxel) been shown to reduce restenosis in animals. Hypothesis This study was designed establish the safety optimal dose systemic ‐paclitaxel reducing in‐stent humans. If...

The analytical characterization of biopharmaceuticals is a fundamental step in the early stages development and prediction their behavior bioprocesses. Protein aggregation particular common issue as it affects all product development. In present work, we investigate stability kinetics A33Fab, therapeutically relevant humanized antibody fragment at wide range pH, ionic strength, temperature. We show that propensity A33Fab to aggregate under thermally accelerated conditions pH ionic-strength...

Nonlinear two-dimensional Fourier transform (2DFT) and linear absorption spectroscopy are used to study the electronic structure optical properties of excitons in layered semiconductor GaSe. At 1s exciton resonance, two peaks identified spectra, which assigned splitting ground state into triplet singlet states. 2DFT spectra acquired for co-linear polarization excitation pulses feature an additional peak originating from coherent energy transfer between triplet. cross-linear pulses, expose a...

RANKIN, JAMES M.; SPINELLI, JOHN. J.; CARERE, RONALD G.; RICCI, DONALD R.; PENN, IAN HILTON, DAVID HENDERSON, MARK A.; HAYDEN, ROBERT I.; BULLER, CHRISTOPHER E. Author Information

Lesions in small-diameter vessels (<3 mm) define a group with distinct clinical and morphological characteristics. There is an inverse relationship between vessel size angiographic restenosis rate. This study assessed whether stents reduce small coronary arteries compared standard balloon angioplasty.We randomly assigned 351 symptomatic patients needing dilatation of 1 native 2.3 2.9 mm to angioplasty alone (n=182) or stent implantation (n=169). The primary end point was at 6 months....

Abstract Objectives: To assess the timeframe of postprocedural complications following transradial percutaneous intervention in selected nonlow‐risk risk patients as a feasibility study for same day discharge. Background: Percutaneous coronary (PCI) is traditionally performed an inpatient procedure. Transradial access with its lower complication rate facilitates safe and We hypothesize that current standards pharmacotherapy intervention, post angioplasty even patient cohort will be evident...

We use optical-pump terahertz (THz)-probe spectroscopy to study carrier dynamics in self-assembled ErAs nanoislands embedded GaAs and deposited a superlattice structure. Measurements are performed at several pump fluences on samples with different periods, enabling determination of the time-dependent conductivity. Subpicosecond capture times obtained, indicating potential these devices as time-domain THz detectors performance comparable low-temperature grown superior control material parameters.

We demonstrate coherent control of cyclotron resonance in a two-dimensional electron gas (2DEG). use sequence terahertz (THz) pulses to the amplitude oscillations an arbitrary fashion via phase-dependent interactions. observe self-interaction effect, where 2DEG interacts with THz field emitted by itself within decoherence time, resulting revival and collapse quantum coherence. These observations are accurately describable using single-particle optical Bloch equations, showing no signatures...

Abstract We present time-integrated four-wave mixing measurements on monolayer MoSe 2 in magnetic fields up to 25 T. The experimental data together with time-dependent density function theory calculations provide interesting insights into the biexciton formation and dynamics. In presence of coherence at negative positive time delays is dominated by intervalley biexcitons. demonstrate that can serve as a control enhance help search for more exotic states matter, including creation multiple...

We have observed cyclotron resonance in a high-mobility GaAs/AlGaAs two-dimensional electron gas by using the techniques of terahertz time-domain spectroscopy combined with magnetic fields. From this, we calculate real and imaginary parts diagonal elements magnetoconductivity tensor, which turn allows us to extract concentration, effective mass, scattering time electrons sample. demonstrate utility ultrafast spectroscopy, can recover true linewidth (>106 cm2V−1s−1) sample without being...

We have observed long-lived (∼30 ps) coherent oscillations of charge carriers due to cyclotron resonance (CR) in high-mobility two-dimensional electrons GaAs perpendicular magnetic fields using time-domain terahertz spectroscopy.The were fitted well by sinusoids with exponentially-decaying amplitudes, through which we able provide direct and precise measures for the decay times oscillation frequencies simultaneously.This method thus overcomes CR saturation effect, is known prevent...

Computationally guided semirational design has significant potential for improving the aggregation kinetics of protein biopharmaceuticals. While improvement in global conformational stability can stabilize proteins to under some conditions, previous studies suggest that such an approach is limited, because thermal transition temperatures (Tm) and fraction unfolded (fT) tend only correlate with where incubated at approaching Tm. This these from globally becomes dominant. However, native are...

A one-dimensional local-mode model is developed to describe phonons propagating normal the layers of (GaAs${)}_{\mathit{n}1}$/(AlAs${)}_{\mathit{n}2}$ superlattices, in which effects broadening interfaces can be quantitatively described. The applied analysis Raman scattering and far-infrared (FIR) measurements on short-period ${\mathit{n}}_{1}$=${\mathit{n}}_{2}$=2,3,. . .,8, shown give a good description data both GaAs AlAs optic-phonon regions using an interface width parameter W 1.4...

We present measurements of the transient photoconductivity in pentacene single crystals using optical-pump terahertz-probe spectroscopy. have measured temperature and fluence dependence mobility photoexcited charge carriers with picosecond resolution. The were excited at 3.0 eV, which is above bandgap ∼2.2 induced change far-infrared transmission was measured. At 30 K, carrier μ≈0.4 cm2/V s decreases to μ≈0.2 room temperature. terahertz signal reveals presence free that are trapped on time...