Imaging of Individual localized modes in 1D Random Laser

  BHUPESH KUMAR  ,  BHUPESH KUMAR [1]  ,  Mélanie Lebental [3]  ,  Patrick Sebbah[1,2]  
[1] 1 Department of Physics, The Jack and Pearl Resnick Institute for Advanced Technology, Bar-Ilan University, Ramat-Gan, 5290002 Israel
[2] 2 Institut Langevin, ESPCI ParisTech CNRS UMR7587, 1 rue Jussieu, 75238 Paris cedex 05, France
[3] 3 Laboratoire de Photonique Quantique et Moleculaire, ENS Cachan, CentraleSup ´ elec, CNRS, Universit ´ e Paris-Saclay, 94235 Cachan, France

Random lasing is reported in solid state PMMA-DCM doped 1D disordered organic microstructure with randomly distributed grooves along the length of dye doped polymer strip.  Role of disorder which is provide by different thickness of dielectric layers separated by 100 nm grooves along the length of polymer strip is shown by the variation in emission spectra of random laser with local pump position. Introduction of long-lived solid state random laser will provide stable emission spectra that will be helpful in control of random laser. Recently we propose an approach to tame random lasers numerically1 and experimentally2, inspired by coherent light control in complex media3. Here, we implement optimization method in an PMMA-DCM solid state laser where modes are localized and slightly overlapped also, which make an ideal case to study localized mode in presence of non linear effect like mode coupling, mode competition and spatial hole burning. We show experimentally single mode lasing operation at any selected wavelength with infinite side lobe rejection.  We image spatial distribution of the electric field intensity of each individual localized modes of a random laser. We find that localized lasing modes are passive mode of the disorder system and there spatial profile and emission wavelength are not affected by presence of gain in disorder media.


       [1]  N. Bachelard, J. Andreasen, S. Gigan, P. Sebbah, “Taming random lasers through active spatial control of the pump”, Phys. Rev. Lett., vol.109, p. 033903 (2012).

[2]  N. Bachelard, S. Gigan, X. Noblin, P. Sebbah, “Adaptive pumping for spectral control of random lasers”, Nature Physics, vol. 10, p. 426-431, 2014.  

[3] Mosk. A,  Lagendijk, A.   “controlling waves in space and time for imaging and focusing in complex media” nature photon. 6, 283-292(2012).