Second harmonic generation and optical parametric amplification in negative-index metamaterials (NIMs) are studied. The opposite directions of the wave vector and the Poynting vector in NIMs results in a “backward” phasematching condition, causing significant changes in the Manley– Rowe relations and spatial distributions of the coupled field intensities. It is shown that absorption in NIMs can...

Second harmonic generation and optical parametric amplification in negative-index metamaterials (NIMs) are studied. The opposite directions of the wave vector and the Poynting vector in NIMs results in a ”backward” phase-matching condition, causing significant changes in the Manley-Rowe relations and spatial distributions of the coupled field intensities. It is shown that absorption in NIMs can...

We realize a microwave quantum-limited amplifier that is directional and can therefore function without the front circulator needed in many quantum measurements. The amplification takes place in only one direction between the input and output ports. Directionality is achieved by multipump parametric amplification combined with wave interference. We have verified the device noise performances by...

Two different pulse cleaning techniques for ultra-high contrast laser systems are comparably analysed in this work. The first pulse cleaning technique is based on noncollinear femtosecond optical-parametric amplification (NOPA) and second-harmonic generation (SHG) processes. The other is based on cross-polarized wave (XPW) generation. With a double chirped pulse amplifier (double-CPA) scheme, a...

Experimental demonstration of the amplification of electrostatic ion-cyclotron waves in a plasma with parallel ion flow shear but no magnetic-field-aligned electron current is presented. Waves with frequencies near the ion gyrofrequency and multiple harmonics launched from an antenna are observed to grow in amplitude in a region of ion flow shear. Amplification of multiple cyclotron harmonics w...

Sharp and highly-selective tunable optical band-pass filters, based on stimulated Brillouin scattering (SBS) amplification in standard fibers, are described and demonstrated. Polarization pulling of the SBS-amplified signal wave is used to increase the selectivity of the filters to 30 dB. Pump broadening via synthesized direct modulation was used to provide a tunable, sharp and uniform amplific...

A simple theoretical model is proposed for the interaction between two counter-propagating laser pulses (a pump and a seed pulse) in unmagnetized plasma. Pulse compression and amplification are observed via numerical simulation. A one dimensional fluid model for stimulated Raman backscattering is proposed to investigate the pulse compression and pulse amplification mechanisms. To accomplish thi...

Silicon core fibers represent a versatile platform for all-fiber integrated nonlinear optical applications. This paper describes the state of art in four-wave mixing-based parametric amplification, and wavelength conversion silicon that have been tapered to improve material quality, engineer dispersion profile. Fibers with submicron dimensions fabricated, used demonstrate high gain amplificatio...

According to the fundamental laws of quantum optics, vacuum noise is inevitably added signal when one tries amplify a signal. However, it has been recently shown that noiseless amplification can be realized phase-sensitive process involved. Two schemes, correlation injection scheme and two-beam amplifier scheme, are both proposed realize multi-way in symmetrical cascaded four-wave mixing proces...

BACKGROUND Previous research has shown positive relationships between dysfunctional cognitive styles and different aspects of pain (eg, pain frequency). One goal of our longitudinal study was to investigate potential risk factors for the incidence of headache (HA) and back pain (BP). METHODS In the first wave (2003), questionnaires were sent to 6,400 children between the ages of 9 and 14 year...