As an advantage, random lasers may be elaborated from a large variety of materials and do not require any cavity oscillators that usually necessitate complicated and expensive fabrication techniques. Since the feedback process of those non-conventional laser systems is provided by light interference in a disordered medium, spectral and temporal uncertainties are usually considered as an intrinsic part of their optical proprieties. We investigated random laser action under two photon absorption experiments through an auto-organized InGaN/GaN quantum-disks ensemble. Thanks to our experimental approach, we evidence random lasing based on a gain medium constituted by point-sized structures. In such context, a stabilised and individual emission mode is observed as for conventional semiconductor lasers. By controlling the emission energy of these nanostructures, a tuneable and stable random laser may be built. Moreover, our findings suggest that disordered medium should play an important role in the conception of low cost quantum dot and up conversion laser systems.
© 2011 Optical Society of America