Random Laser Action in Semiconductor Powder

TLDR

Recurrent light scattering occurs when the scattering mean free path is shorter than the emission wavelength, providing coherent feedback for lasing. The study reports the first observation of random laser action with coherent feedback in semiconductor powder, revealing discrete lasing modes above threshold, an intensity–volume dependence consistent with random laser theory, omnidirectional emission, and direct evidence of recurrent light scattering.

Abstract

We report the first observation of random laser action with coherent feedback in semiconductor powder. Since the scattering mean free path is less than the emission wavelength, recurrent light scattering arises and provides coherent feedback for lasing. Discrete lasing modes have been observed above the threshold. The dependence of the lasing threshold intensity on the excitation volume agrees with the random laser theory. Laser emission from the powder could be observed in all directions. This observation also provides direct evidence for the existence of recurrent scattering of light.