An optofluidic router in a low-cost (PDMS) platform for rapid parallel sample analysis

Abstract

Optofluidic system for (bio)chemical applications are becoming more demanding in terms of num- ber of control points, number of light sources and readout equipment. So far, most of these sys- tems require several light sources/detectors for suitable performance, increasing their complexity and cost. In this work, we present an easily integrated, fluidically controlled optical router that fa- cilitates coupling of several light sources or detectors. By using PDMS mirrors and phaseguides, the switching liquid is guided and pinned in desired angles, so that the incident light undergoes total internal reflection and can be reflected towards the output channels without any movable parts. The developed router presents ideal performance for lab on a chip applications, achieving switching frequencies between 0.07 ± 0.025 and 4 ± 2 Hz, depending on the flow rate of the switching liquid. The cross-talk levels are at 20 dB from channel output power to static noise level. With the use of parabolic mirrors, channel coupling efficiencies decrease just 2.38 dBm over four channels. The dynamic switching noise reduces the cross-talk levels by 2-5 dB, depending on the incorporation of ink-apertures. The insertion loss of these devices ranges from 17.34 to 25.42 dB. These results prove the viability of the fluidically controlled router in the low-cost PDMS platform. The intended goal of this work has been to simplify and speed up parallel sample analysis with the router integrated into a multiple path photonic component on a single chip. Development on this front is ongoing to rapidly measure methadone concentrations on chip.