Phase-locked coherent modes in a patterned metal-organic microcavity
Dr. Alex Zakhidov
The Fraunhofer Research Institution for Organics, Materials and Electronic Devices COMEDD, 01109 Dresden, Germany
Abstract
Organic microcavities offer tantalizing prospects for studying the interactions of light and matter. In particular, the large oscillator strengths and exciton binding energies of organic semiconductors make them attractive for investigating coherent non-linear phenomena. Previously, polariton lasing and condensation were only observed in GaAs- and CdTe-based microcavities, mostly at cryogenic temperatures. Exciton-polariton lasing (S. Kena-Cohen, S.R. Forrest, Nat. Phot. 4, 371 2010) and cavity photon condensation (J. Klaers, et al. Nature 468, 545 2010) have recently been demonstrated in organic microcavities at room temperature. In order to apply these processes in an electrical device, electrodes must be integrated. However, such integration is extremely challenging because of the large absorption of metals, which is generally considered fatal for the development of coherence.
In this work, we engineer the density of states of an organic microcavity by embedding a periodic metal structure into it. Thereby, we generate arrays of localized cavity polaritons and Tamm plasmon-polaritons inside the cavity. These excited states are capable of phase coupling across the metal grating. Under nonresonant excitation and at room temperature, we selectively stimulate coherent emission from in- and out-of-phase locked coherent arrays. Thereby, we do not only demonstrate that the presence of metal inside an optical cavity is compatible with coherent emission but also that these particular periodic structures modify the density of states to allow for selective excitation of different new modes. Besides such rich photophysics, our strategy of embedding metal patterns into an organic microcavity yields a viable route towards electrically driven organic solid state lasers.
Dr. Alex Zakhidov CV facts:
Sept. 2006
PhD in Physics of Solid State
Moscow State University (MSU), Physics Department, Russia.
PhD Thesis: "Field electron emission properties of nano-carbon materials".
PhD Advisor - prof. A.N. Obraztsov
Dec. 2006 - Mar. 2007
Visiting researcher
Nanotech Institute, The University of Texas at Dallas, Richardson, Texas, USA.
Conducted research on electrochemical double-layer charge injection of carbon nanotube (CNT) films with liquid and solid electrolytes.
Apr. 2007 - Mar. 2010
Postdoctoral Fellow
Cornell University, Department of Materials Science and Engineering Ithaca, New York, USA.
Conducted research on novel processing and patterning approaches for organic electronic and optoelectronic systems.
May 2010 - Dec. 2011
Alexander von Humboldt Fellow,
Institut für Angewandte Photophysik, Dresden University of Technology, Dresden, Germany.
Conducting research on device physics of organic electronic and optoelectronic systems.
Jan. 2012 - present
Group Leader
The Fraunhofer Research Institution for Organics, Materials and Electronic Devices COMEDD, Dresden, Germany.
FhG "ATTRACT" project: OLED Microdisplay Fabrication by Orthogonal Photolithography.