We investigate second-harmonic generation in a nonlinear photonic crystal having radial quasi-periodic order and continuous rotational symmetry. This device enables us to simultaneously phase match different nonlinear interactions in any arbitrary direction of propagation. We have fabricated such a crystal by electric field poling of a magnesium-doped stoichiometric LiTaO(3) and demonstrated fr...

An integrated electro-optic waveguide modulator is demonstrated in bulk fused silica. A Mach-Zehnder interferometer waveguide structure is fabricated by direct writing with a femtosecond laser followed by thermal poling. A 20 degrees electro-optic phase shift is achieved at an operating wavelength of 1.55 microm with an applied voltage of 400 V and an interaction length of 25.6 mm, which corres...

We show that the nonlinearity in periodically poled photovoltaic photorefractives can be solely of the cross-phase-modulation type. The effects of self-phase modulation and asymmetric energy exchange, which exist in homogeneously poled photovoltaic photorefractives, can be considerably suppressed by the periodic poling. Finally, we demonstrate numerically that periodically poled photovoltaic ph...

The lower extremity dexterity test quantifies sensorimotor control for cross country skiing. Introduction: Research on top-level crosscountry skiing ability is predominately centered on the athlete´s physical fitness, biomechanical aspects of the skiing technique, and materials that make up ski hardware. Results concerning aerobic endurance capacity have been extended by new findings regarding ...

The purpose of this study is to create and evaluate a smart composite structure that can be used for integrated load sensing and structural health monitoring. In this structure, PVDF films are used as the matrix material instead of epoxy resin or other thermoplastics. The reinforcements are two layers of carbon fiber with one layer of Kevlar separating them. Due to the electrical conductivity p...

PURPOSE To further the understanding of double poling (DP) through biomechanical analysis of upper and lower body movements during DP in cross-country (XC) skiing at racing speed. METHODS Eleven elite XC skiers performed DP at 85% of their maximal DP velocity (V85%) during roller skiing at 1 degrees inclination on a treadmill. Pole and plantar ground reaction forces, joint angles (elbow, hip,...