Enhancing signal quality of evanescent-wave multimode fiber optic sensor using diffuse excitation light

In a typical evanescent-wave-based optical device, Whether using fiber optics, free space or a lab-on-a-chip, the signal is not only weak but often mixed with a strong stray excitation (Ex) light. This leads to a requirement for a high-performance filter and detector assembly for signal recovery and thus adds a major cost to the entire system. We propose a non-Lambertian type light diffuser, offering a highly efficient novel use of Ex. power to simultaneously achieve a stronger fluorescent signal and reduce the stray Ex power level. Particular attention is given to how this universal concept can be applied to a lab-on-a-chip device.