Sensitivities of InGaAsP photonic crystal membrane nanocavities to hole refractive index

The sensitivities of resonant wavelengths of photonic crystal (PhC) membrane nanocavities with embedded InAs quantum dots to the ambient refractive index are reported for use in (bio) chemical sensing. The resonances for the different modes of several point-defect type cavities are obtained by photoluminescence measurements. Systematic trends of the variation of sensitivity with increase of the overlap of the modes with the PhC holes are observed for varying cavity type as well as for a given mode within a cavity type. A maximum sensitivity of approximately 300 nm/RIU (refractive index unit) is observed, corresponding to approximately 25% mode overlap with the holes and complete infiltration with the aqueous solution.