Nonlinear dynamics at the meso- and nanoscale: stochasticity meets determinism

Application-driven technological progress has led to the realization of lasers whose cavity volume is below one cubic emission wavelength. Such nanodevices possess features which differ from those of standard, macroscopic lasers, such as thresholdless behaviour. We discuss the dynamics in lasers ranging from the mesoscale down to the nanoscale and highlight the impact of noise on the operation of systems below the macroscopic scale. Experimental and modeling issues are discussed, together with the needs for interpretative tools geared towards the investigation of these new devices, which are poised to play a substantial role in future applications and in the study of the dynamics of small systems, at the crossing points between determinism, stochasticity, finite size, and quantum effects.