We propose and experimentally demonstrate the generation of single-cycle terahertz radiation with two-stage optical rectification in GaSe crystals. By adjusting the time delay between the pump pulses employed to excite the two stages, the terahertz radiation from the second GaSe crystal can constructively superpose with the terahertz field injected from the first stage. The high mutual coherenc...

Here we demonstrate an unusual type of superradiance in extended layer a two-level medium excited by pair unipolar pulses. It is shown that, due to the interference secondary waves emitted resonant medium, response such reflection represents half-cycle pulses different polarity. They follow with time delay proportional thickness. The source monopolar pulse stopped polarization induced first exc...

Intense sub-5-fs pulses were generated by filamentation in a noble gas and subsequent chirped-mirror pulse compression. The transversal spatial dependence of the temporal pulse profile was investigated by spatial selection of parts of the output beam. Selecting the central core of the beam is required for obtaining the shortest possible pulses. Higher energy efficiency is only obtained at the e...

Experimental facilities for picosecond X-ray spectroscopy and scattering based on RF deflection of stored electron beams face a series of optical design challenges. Beamlines designed around such a source enable time-resolved diffraction, spectroscopy and imaging studies in chemical, condensed matter and nanoscale materials science using few-picosecond-duration pulses possessing the stability, ...

We investigate the system of a heavy impurity immersed in degenerated Fermi gas, where impurity's internal degree freedom (pseudospin) is manipulated by series radiofrequency (RF) pulses at several different times. Applying functional determinant approach, we carry out an essentially exact calculation Ramsey-interference-type responses to RF pulses. These are universal functions multiple time i...

introduction : the fast-growing telecommunication and wireless technologies has led to more dependence to these communication devices and higher levels of exposure to electromagnetic radiations propagated by cellular devices and their service towers. to disable signaling in places where silence is valued or where information quarantine measures are required, mobile phone jammers emit radiofrequ...

Lionel Tarassenko Dept. of Eng. Science, University of Oxford, Parks Road, Oxford, OX1 3PJ United Kingdom. We describe pulse stream firing integrated circuits that implement asynchronous analog neural networks. Synaptic weights are stored dynamically, and weighting uses time-division of the neural pulses from a signalling neuron to a receiving neuron. MOS transistors in their "ON" state act as ...

1. Twelve healthy subjects received high-voltage pulsed galvanic stimulation (115-475 V d.c.) delivered in separate treatments of 2, 32 and 128 pulses/s for 10 min at the subject's maximum tolerable voltage while calf muscle blood flow was measured by non-invasive Whitney strain-gauge venous occlusion plethysmography. 2. The high-voltage pulsed galvanic stimulation was administered with negativ...