Abstract

Due to their deeply subwavelength field concentration over a very broad (THz level) resonance bandwidth, nano-antennas are widely used for sensing and enhancing light-matter interactions [1]. Microcavities can serve similar goals, but in a different way: they make use of high optical quality factors in combination with modest mode volumes [2]. Combining both in a hybrid plasmonic-photonic system could yield, for example, extreme spontaneous emission enhancement or efficient sensing over a highly tunable bandwidth. Such a hybrid system will naturally exhibit resonant modes that combine traits of its constituents. In this research we experimentally study these modes to determine the strength and nature of antenna-cavity coupling. In a suitably engineered system, we observe anomalous alteration of cavity resonance frequencies and linewidths when nano-antennas perturb a microcavity. Systematic variation of constituent parameters allows to identify coupling mediated by radiation channels as the source of these effects, which run contrary to the expectations of standard cavity perturbation theory [3].

© 2015 IEEE