Events

23 January

In searching of a measure of coupling between random lasers

Thursday 23 January 2020, 12:00pm

ICN2 Seminar Hall, ICN2 Building, UAB

Prof. Ceferino López, Instituto de Ciencia de Materiales de Madrid (ICMM); Consejo Superior de Investigaciones Científicas (CSIC), Spain 

Abstract: In random lasers (RLs) the optical feedback is provided by multiple light scattering occurring in disordered media [1]. They have been established as alternative laser sources with low spatial coherence, suitable for imaging and lighting applications [2].

Owing to their intrinsic nonlinear nature, networks of RLs can open up new perspectives in the roadmap of neural networks for artificial intelligence applications. The influence exerted on a RL within a network of connected peers can be used as cellular interactions and the emission spectral correlations as their fingerprints.

Here, I report simple networks of RLs (of localized feedback) and, by analysing the spectral correlations, prove that the emission of a given RL can be altered if it shares a scattering centre with other resonators, thus creating a synapse.

Single RL features can be prepared in the fabrication stage (by direct-laser-writing cylindrical holes on a dyedoped biopolymer film) [3-4].

Establishing that a node’s emission is altered by other resonators’ influence has proved an easy task for a trained human eye but a tough one for mathematical algorithms based on Pearson’s correlation, mutual information, variance and skewness of intensity ratio distributions, etc. that only work for single peak spectra and turn out to be equivalent.

References

  • [1] S. Gottardo, R. Sapienza, P.D. García, Á Blanco, D.S. Wiersma, C. López., Nat Photon. 2:429–32 (2008).
  • [2] B. Redding, M.A. Choma, H. Cao, Nat. Photon. 6, 355–359 (2012).
  • [3] A. Consoli, E. Soria, N. Caselli, and C. López, Opt. Lett., 44, 3, 518 (2019).
  • [4] A. Consoli and C. López, Sci. Rep., 7, 40141, (2017).

 

Hosted by Prof. L. Lechuga Nanobiosensors and Bioanalytical Applications Group Leader and Prof. D. Maspoch, Supramolecular Nanochemistry and Materials Group Leader at ICN2