Neuromimetic Dynamics in a Micropillar Laser with Saturable Absorber

We study the neuromimetic properties of a micropillar laser with saturable absorber. The investigated properties are: excitability, refractory periods and temporal summation. The absolute refractory period is the amount of time after a first excitable pulse has been emitted during which it is not possible to excite the system anymore. The relative refractory period is the time after a first excitable pulse during which an inhibited response is emitted. Temporal summation happens when two or more input perturbations below the excitable threshold and separated by a temporal delay lead to one excitable response. These properties could be found in excitable systems in general and neurons in particular and has been often studied in some optical systems. Fast excitable, neuron-like, response with a duration of 200 ps, which is 7 orders of magnitude faster than in biological neurons, is experimentally demonstrated. Relative and absolute refractory periods are evidenced in this system (respectively 200 - 350 ps and 200 ps). Temporal summation of two input perturbations is evidenced and a critical summation delay between input pulses of 600 ps in measured. The experimental results are well described qualitatively by a simple model of a laser with saturable absorber. Refractory periods and temporal summation proves that a micropillar laser with saturable absorber has a memory of its past history. Refractory periods are also responsible of the unidirectional propagation in neurons. These work pave the way for the realization of 2D networks of neuromimetic coupled micropillars laser with saturable absorber.