Propagation of ultrashort pulses in single-mode fiber

Propagation of ultrashort pulses in dispersing media and optical fibers is calculated and analyzed. An analytical expression for the electric field of ultra short pulse after propagating certain distance z is derived in the second order dispersion theory. The propagation of a Gaussian pulse is considered. ultra-short pulses, optical fiber, dispersion

Diffraction of ultrashort pulse on a nanoscale conductive cone

Surface plasmon polariton is collective oscillation of the free electrons at metal dielectric interface. As a wave phenomenon, surface plasmon polaritons can be focused using appropiate excitation geometry of metallic structures. We theoretically demonstrate the possibility of controlling nanoscale short pulse superfocusing based on the generation of radially polarized surface plasmon polariton mode of conical metallic tip. Numerical simulation for femtosecond pulse propagation along a silver nano-needle is discussed. The spatial distribution for a near field strongly depends on a linear chirp of the laser pulse which can partially compensate the wave dispersion. Field distribution is calculated for different chirp values, opening angle 0.1, distances ri = 1000 nm and rf = 250 nm. For a pulse with a chirp β =-0.013 fs1, pulse duration becomes shorter and changes from 32 fs to 18.8 fs, and field amplification is equal to 42.7

Modification of the EDXD method for diagnostics of polycrystalline and fine-grained media

The possibilities of using broadband X rays for diagnostics of the atomic structure of solids are considered. It is proposed to use virtual photons of the Coulomb field of a relativistic electron beam as primary probe radiationye

Efficient Use of User Interface: the Circle Mobile Application

Исследуется роль дизайна пользовательского интерфейса в обеспечении эффективного использования в рамках мобильного приложения «Сёркл». Основываясь на теории эффективного использования, тестируется четыре различных пользовательских интерфейса, разработанных для задач частого ввода данных в мобильном приложении, с помощью контролируемого эксперимента и последующего опроса. Результаты показывают, что дизайн пользовательского интерфейса с точки зрения техники ввода (касание или скольжение) и направления цели (вертикальное против горизонтального) оказывает значительное влияние на время выполнения задач, а также на воспринимаемое удобство и привлекательность пользовательского интерфейса приложения.This paper explores the role of user interface design in ensuring effective usage within a mobile app, Circle. Based on effective usage theory, four different user interfaces designed for the task of frequent data entry in a mobile application are tested using a controlled experiment and a follow-up survey. The results show that user interface design in terms of input technique (tapping or sliding) and target direction (vertical vs. horizontal) has a significant impact on task execution time as well as on the perceived usability and attractiveness of the application’s user interface