Enhancement of the optical nonlinearity in pseudoisocyanine J aggregates embedded in distributed feedback microcavities

Coherent transients of pseudoisocyanine J aggregates in distributed feedback microcavities are reported. Under the resonant excitation of the cavity-mode observed at the low-energy side of the excitonic resonance, the response time is about 0.5 ps, approximately equal to the pump–pulse duration. We find the enhancement of the optical nonlinearity by one order of magnitude in the microcavity. The excitation of the dielectric-band mode is effective to enhance the nonlinearity with the ultrafast response.