Propagation in active GRIN materials: comparison between parabolic and hyperbolic secant complex refractive index profiles

Abstract

Effects of gain or loss on the propagation of light beams through active GRIN media are discussed. Complex refractive indices are studied to discuss what gain or loss means in terms of the real and imaginary parts of them. The real part of the refractive index determines the guidance behavior of the active material and the gain or loss is determined by the sign of the imaginary part of the refractive index. Comparison between Gaussian beam propagation in active GRIN media with parabolic refractive index profile and hyperbolic secant refractive index profile is outlined.