Fluorescence Enhancement Utilizing Dielectric Microbeads with Semi-open Microwells

Abstract

Dielectric microbeads can converge light into a narrow beam with high intensity which allows for enhancing the fluorescent signals. However, a critical challenge for the experimental realization is introducing the fluorescent samples into this extremely small beam area. Here, we design and fabricate dielectric microbeads with semi-open microwells in which localized converging light beam of high intensity can be generated. We show that fluorescent microspheres can be efficiently loaded into the semi-open microwells and thus simultaneously illuminated by the converging beam generated by the micro-optical structures without any further manipulations. Pronounced fluorescent enhancement of around 9 folds can be obtained in comparison with the fluorescent microspheres on glass substrates, stemming from the excellent convergent effect of this micro-optical structure.