One-mirror random laser

A one-mirror random laser is described. The necessary feedback is from random scattering inside a disordered medium and a reflective mirror together. With such a half-random and half-conventional cavity, the lasing threshold can be reduced dramatically, especially for systems in the localized regime, where the lasing threshold is otherwise very difficult to reach by optical pumping. The threshold decrease is due to better overlap between the pumped region and lasing modes, as well as the different eigenmode structure of the half-close system. An Anderson-type lattice Hamiltonian model was used to investigate the decay rate distributions in one-dimensional systems open at one end and at both ends. Analysis on the small decay rate tail showed an enhancement of localization in the former kind of systems.