We experimentally demonstrate generation of high-intensity short optical pulses obtained by the controlled ultrafast release of the stored energy confined in silicon microcavities. This is achieved using ultrafast tuning of the coupling from a coupled-ring cavity to an external waveguide on time scales shorter than cavity photon lifetime.

PURPOSE The purpose of this study was to investigate the value of UltraFast Doppler ultrasonography (US) for evaluating hepatic vessels in liver recipients. METHODS Thirty-nine liver Doppler US sessions were conducted in 20 liver recipients. Each session consisted of UltraFast and conventional liver Doppler US in a random order. We compared the velocities and phasicities of the hepatic vessel...

PURPOSE To compare an ultrafast CT method for estimating regional cerebral blood flow with a more commonly used xenon-enhanced CT method. METHODS Xenon CT and ultrafast CT were used to estimate regional cerebral blood flow (rCBF) in 12 healthy beagle dogs. Measurements were obtained for left and right hemisphere, cortical gray matter, basal ganglia, and deep white matter. The ability of each ...

BACKGROUND Ultrafast computed tomography (CT), by acquiring images of the proximal coronary arteries, detects coronary calcifications and has been demonstrated to be highly sensitive for the detection of coronary artery disease in many small studies. The aim of this study was to determine the relationship between ultrafast CT scanning and coronary angiography in a large number of symptomatic pa...

Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafas...

We present a method for the generation of high kinetic energy attosecond electron packets via magnetostatic and aperture filtering of conical surface plasmon (SP) accelerated electrons. The conical SP waves are excited by coupling an ultrafast radially polarized laser beam to a conical silica lens coated with an Ag film. Electromagnetic and particle tracking models are employed to characterize ...

We track the dynamic response of GaAs quantum-well semiconductor diode lasers after injection of a femtosecond pulse, using ultrafast upconversion. The continuous-wave emission shows gain dynamics and relaxation oscillations on timescales of 1–100 ps. The recirculating femtosecond pulse evolves into an ultrafast ‘‘dark pulse’’ in the wake of subpicosecond oscillations. © 1998 American Institute...

Abstract Consider a scenario where quantum particle is initially prepared in some bounded region of space and left to propagate freely. After time, we verify if the has reached distant target region. We find that there exist ‘ultrafast’ (‘ultraslow’) states, whose probability arrival greater (smaller) than any classical same with momentum distribution. For both projectiles rockets, prove advant...