ELECTROMAGNETIC LOCALIZATION IN ONE-DIMENSIONAL STACKS WITH RANDOM LOSS AND GAIN

We study both analytically and numerically the properties of a one-dim ensional stack consisting of layers with the same thickness, but rando m complex refractive indices. Thus the stack as a whole may exhibit lo ss or gain. We present a simple expression for the localization length in the domain of intermediate and long wavelengths. For short wavelen gths we show that, in contrast to the case of a stack with layers havi ng real refractive indices, the localization length tends to zero as a linear function of the wavelength, rather than approaching a nonzero constant. Numerical calculations confirm the analysis.