Low-threshold and quasi-single-mode random laser within a submicrometer-sized ZnO spherical particle film

An unique random laser exhibiting quasi-single-mode and low lasing threshold is developed by a homogenized submicrometer-sized zinc oxide particle film dispersed with intentionally introduced polymer particles as point defects. Such unique random lasing is dominantly initiated at the defect sites, although multi-mode peaks with a collapsed broad emission spectrum are observed at the defect-free sites as in the conventional random lasers. Thus our proposed simple structure can possibly provide the controllability of lasing properties even in random structures. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4792349]