Enhancement of fluorescence signal with one dimensional photonic band gap structure

摘要

In this paper, we propose to use one dimensional (ID) photonic band gap (PBG) structure to enhance the florescence excitation and collection for single molecule level imaging and sensing applications. In the setup, the incidence of excitation and the collection of the florescence are located on separate sides of the ID PBG structure. The ID PBG structure creates total internal reflection for the excitation wavelength. With carefully chosen ID PBG structures, an enhanced evanescent field for the excitation wavelength at the interface between the last layer of the PBG and sample can be obtained. Meanwhile, the ID PBG structure is designed such that it also serves as an omnidirectional reflector for the florescence signal, leading to higher collection efficiency. The combination of stronger excitation field and improved detection efficiency gives rise to two orders of magnitude enhancement of florescence signal.