Observation of strong exciton-photon coupling in an organic microcavity

An optical organic semiconductor microcavity showing the strong coupling re gime was prepared. The dye 1,1 ' -diethyl-2,2 ' -cyanine (PIC) forming J-ag gregates was used as optically active material in a planar lambda /2-microc avity configuration. Stable thin layers of homogeneously distributed aggreg ates without any matrix were prepared by spin-coating of a specific salt of the dye [(PIC+)(2)B10H102-]. Strong exciton-photon coupling was demonstrat ed by the anticrossing of exciton and photon modes. A Rabi-splitting of mor e than 50 meV was observed in transmission measurements. The asymmetric nor mal mode splitting could be explained by the asymmetric absorption spectrum of the J-aggregate. (C) 2001 Elsevier Science B.V. All rights reserved.