In a previous Letter [Tsang and Psaltis, Opt. Lett.31, 2741 (2006)], we assert that the total reflection coefficient of two dielectric slabs goes to zero in the limit of single-waveguide resonance. A more careful derivation shows that this is not the case. The correct condition in which reflectionless evanescent-wave amplification can be achieved by two dielectric planar waveguides is derived i...

Many-particle time domain methods are rising alternatives to particle-in-cell (PIC) or frequency simulate the wave–beam interactions in traveling wave tubes (TWTs). We focus on two of those: our Hamiltonian discrete model DIMOHA is compared analytically against pseudospectral method RUBEUS. Although based completely different approaches—the Gel’fand transform for and telegraphist circuit RUBEUS...

We consider the problem of amplification of an optical signal wave with an optical pump wave when both are propagating in the fundamental mode of a single mode optical waveguide. We introduce a system of Ginzburg–Landau type and study the radiation loss due to the nonlinear interaction between the signal and the pump waves. The linear dynamics are dispersive, while nonlinearity governs the tran...

We present a statistical analysis of freak waves1 measured during the 203 h of observation on sea surface elevation at a location in the coastal zone of the Baltic Sea (2.7 m depth) during June–July 2008. The dataset contains 97 freak waves occurring in both calm and stormy weather conditions. All of the freak waves are solitary waves, 63% of them having positive shape, 17.5% negative shape and...

The possibility of observing acoustic-wave amplification made possible through the heating of neutral particles by electrons in a weakly ionized gas has received some recent attention. -4 The idea is that an existing sound wave, by inducing a space-.time variation in the electron density, would create an acoustic source, thereby generating a wave that interferes constructively with the original...

We extend the Miles mechanism of wind-wave generation to finite depth. A β-Miles linear growth rate depending on the depth and wind velocity is derived and allows the study of linear growth rates of surface waves from weak to moderate winds in finite depth h. The evolution of β is plotted, for several values of the dispersion parameter kh with k the wave number. For constant depths we find that...