New Types of Orthonormal Electromagnetic Beams in Complex Media and Free Space
Abstract : Vector plane-wave superpositions defined by a given set of orthonormal scalar functions on a two- or three- dimensional manifold are treated. We present a technique for composing orthonormal electromagnetic beams in complex media and free space. New families of exact time-harmonic solutions of the homogeneous Maxwell equations in linear media (isotropic, chiral, anisotropic, and bianisotropic) and free space, which describe orthonormal electro magnetic beams, are obtained.
Orthonormal Beams with Applications to Characterizing Electromagnetic Fields and Complex Mediums
Summary We present an approach to characterizing electromagnetic fields and complex mediums, based on the use of new families of electromagnetic beams. They are defined by a given set of orthonormal scalar functions on a two- or three-dimensional manifold. Each family consists of orthonormalexact solutions of Maxwell's equations, which differ substantially from thewell-known approximate solutions (the Hermite-Gaussian and Laguerre-Gaussian beams). A promising type of such beams-orthonormal beams defined by thespherical harmonics-is discussed. The proposed approach makes it possible to characterize complex mediums by using beams focused into a small spot on the sample surface.
An analytical approach to the design of electrodes in high-power, fast-transverse-flow CO2 lasers
Abstract Usually, the design of the electrodes of fast-transverse-flow CO 2 lasers relies more on experimental data than on theoretical analysis. Traditional systems sustain a stable, high-power discharge but the current distribution generates a peaked, non-uniform small-signal-gain pattern. We present a theoretical model suitable for the design of electrodes that achieves a quasi uniform gain distribution. The analysis, based on a two-temperature model and the gas-transport equations, computes the electron density that supports a flat gain pattern. Combining the desired electron density with the electron-balance equations, the model determines the required electric field. The results were used to design a new set of electrodes for a home-made fast transverse flow CO 2 laser. A stable, large volume discharge ( 4 × 8 × 90 cm 3 ) with very good uniformity was obtained. The resulting gain distribution was registered in a bi-dimensional map. The peak gain rose from 1.2 m - 1 , attained with the old electrode set, to 1.6 m - 1 with the new one and the gain showed a homogeneous profile.