Herrera, FelipePeropadre, BorjaPachon, Leonardo AugustoSaikin, Semion K.Aspuru-Guzik, Alan2014-12-092014Herrera, Felipe, Borja Peropadre, Leonardo Augusto Pachon, Semion K. Saikin, and Alán Aspuru-Guzik. 2014. “Quantum Nonlinear Optics with Polar J-Aggregates in Microcavities.” Journal of Physical Chemistry Letters 5 (21) (November 6): 3708–3715. doi:10.1021/jz501905h.1948-7185http://nrs.harvard.edu/urn-3:HUL.InstRepos:13479132We predict that an ensemble of organic dye molecules with permanent electric dipole moments embedded in a microcavity can lead to strong optical nonlinearities at the single-photon level. The strong long-range electrostatic interaction between chromophores due to their permanent dipoles introduces the desired nonlinearity of the light–matter coupling in the microcavity. We develop a semiclassical model to obtain the absorption spectra of a weak probe field under the influence of strong exciton–photon coupling with the cavity field. Using realistic parameters, we demonstrate that a cavity field with an average photon number near unity can significantly modify the absorptive and dispersive response of the medium to a weak probe field at a different frequency. Finally, we show that the system is in the regime of cavity-induced transparency with a broad transparency window for dye dimers. We illustrate our findings using pseudoisocyanine chloride (PIC) J-aggregates in currently available optical microcavities.en-USJ-aggregatesoptical microcavityquantum nonlinear opticscavity-QEDelectromagnetically induced transparencyJournal Article2014-12-0910.1021/jz501905h