Enhanced Fluorescence-Based Optical Sensor Performance Using a Simple Optical Collection Strategy

In this letter, we report a simple optical strategy designed to significantly enhance the fluorescence collection efficiency of planar substrate-based optical sensors. The strategy involves the use of refractive and reflective optical elements that permit supercritical angle fluorescence to be transmitted through the lower surface of the planar substrate and redirected toward an optical detector. Importantly, this approach facilitates simple integration with existing multianalyte sensor systems and microfluidic platforms by leaving the sensor's upper planar surface unstructured. In comparison to a conventional planar substrate configuration, the proposed approach can provide better than an order of magnitude (factor of 20) enhancement in the fluorescence intensity detected. It is envisaged that this approach will have significant potential in a range of application areas where there is need for low-cost optical sensor technologies.