Abstract

Interference effects of light in highly scattering medium can result in Anderson localization. In this case, stationary solutions of the wave equation are spatially localized modes. By introducing nonlinear amplification in such a medium, important issues are in order. Is Anderson localization preserved in the presence of gain? Is laser action possible in a disordered media? In recent experiments, Cao et al. [1] have demonstrated laser action in highly disordered semiconductor powders. This effect is interpreted in terms of amplification along closed loop paths which play the role of ring cavities. However, it is not completely clear that this observation can be interpreted in terms of localization of light. Although the mean free path measured was comparable to the optical wavelength, evidence of Anderson localization of light in these samples was not established.

© 2000 IEEE