Hybrid system of different shapes of gold nanoparticles on microcavity to study Purcell's effect

Whispering gallery modes (WGMs) occur due to total internal reflection in symmetric dielectric structures. These modes have high quality (Q) factor and low mode volume (Veff). Photoluminescence (PL) of an emitter when coupled with WGMs leads to the modification in the radiative rate of the emitter. This effect on the radiative rate is known as Purcell effect. Purcell factor (FP) is proportional to Q/Veff of the cavity. Localized surface plasmon resonance (LSPR) of metal nanoparticles (NPs) can be used along with the WGMs of the microcavity to have a combined LSPR-WGM hybrid system. LSPR depends on the shape and size of the NPs which can affect FP of the microcavity. In this work, we report the effect of octopod and octahedral shaped gold nanoparticles (AuNPs) on the radiative rate of rhodamine B (RB) doped microspheres. FP values of smaller than unity have been observed indicating the inhibition of the radiative rate in the microcavity.