Transient Optical Characteristics of Broad Absorption Band Excitons Modulated by Micro-cavity

The understanding of light-matter interaction within micro-cavity lays the basic groundwork for many future photon-related technologies and applications. We prepared low quality metal-insulator-metal(MIM) micro-cavity consisting massive two-level broad absorption band dye(Nile Red) excitons, which randomly dispersed in SU-8 polymer negative resist matrix and measured their optical characteristics. New binate transmission peaks with large energy separation(so-called Rabi-splitting phenomenon) and their angular anti-crossing behavior in consequence of the interaction between dye excitons and confined photons were observed. It was also confirmed that the separated energy can be tuned by changing the doped exciton concentrations. Time-resolved transient absorption measurements showed that such an interaction is indeed a coherent one but rather a strong coupling one and one can modulate such a coherent mechanism by easily adjusting the detuning between dye excitons and confined cavity photons. This work may provide a comprehensive and deep understanding for such massive broad absoprtion band excitons-doped MIM micro-cavities and represent a further step to realize optical cavity-modulated devices in future.