Random lasing mode alterations by single-nanoparticle perturbations

We numerically demonstrate that alterations in random lasing modes can serve as a highly sensitive biosensing mechanism for single-nanoparticle quantitation. In our approach, subtle perturbations from a single nanoparticle can induce dramatic changes in multiple eigenmodes in disordered structures that can be detected by spectral variations of lasing emission peaks. Several resonance mode frequencies show relatively linear spectral responses to nanoscale perturbations, and each mode possess different levels of perturbation sensitivity. We also show that such behavior exists in both highly and loosely packed disordered media. We envision that the simplicity of such realization will facilitate the biosensor development using random lasers. (C) 2012 American Institute of Physics. [doi:10.1063/1.3675885]