Polymer waveguide backplanes for optical sensor interfaces in microfluidics

Abstract

A polymer optical backplane capable of generic luminescence detection within microfluidic chips is demonstrated using large core polymer waveguides and vertical couplers. The waveguides are fabricated through a new process combining mechanical machining and vapor polishing with elastomer microtransfer molding. A backplane approach enables general optical integration with planar array microfluidics since optical backplanes can be independently designed but still integrated with planar fluidic circuits. Fabricated large core waveguides exhibit a loss of 0.1 dB cm(-1) at 626 nm, a measured numerical aperture of 0.50, and a collection efficiency of 2.86% in an n = 1.459 medium, comparable to a 0.50 NA microscope objective. In addition to vertical couplers for out-of-plane collection and excitation, polymer waveguides are doped with organic dyes to provide wavelength selective filtering within waveguides, further improving optical device integration. With large core low loss waveguides, luminescence collection is improved and measurements can be performed with simple LEDs and photodetectors. Fluorescein detection via fluorescence intensity with a limit of detection (3sigma) of 200 nM in a 1 microL volume is demonstrated. Phosphorescence lifetime based oxygen detection in water in an oxygen controllable microbial cell culture chip with a limit of detection (3sigma) of 0.08% or 35 ppb is also demonstrated utilizing the waveguide backplane. Single waveguide luminescence collection performance is equivalent to a back collection geometry fiber bundle consisting of nine 500 microm diameter collection fibers.

Organic solid‐state integrated amplifiers and lasers

“…This reduces the number of fabrication steps, allows for fabrication of photonic lab-on-chip systems with a higher degree of miniaturization. Backplanes are usually made of low-cost polymeric materials such as PMMA and PDMS, which besides its elasticity, optical transparency and ease of processing by soft lithographic techniques it also offers the advantage of biocompatibility for applications that it is required [294,295].…”

Interaction of guided light in rib polymer waveguides with dielectrophoretically controlled nanoparticles

“…The development and applications of optical devices integrated with microfluidics have been previously suggested (Schmidt and Hawkins 2008;Applegate et al 2006;Ateya et al 2008;Bernini et al 2008;Li et al 2008;Lien et al 2004;Sheridan et al 2009;Tang et al 2008;Whitesides 2006;Datta et al 2003;Lee et al 2007;Jiang et al 2010). In particular, integrated microfluidic systems capable of manipulating properties of optical signals have been demonstrated (Domachuk et al 2006;Hitz 2006;Mach et al 2002).…”

A guiding light: spectroscopy on digital microfluidic devices using in-plane optical fibre waveguides

“…In the case of microchannel-based microfluidics, optical detection has proven popular because of the small instrumentation footprint and ease of integration with devices [5]. Several innovations have further enhanced the utility of optical detection in microchannels, including device-integrated reflectors [4,6], filters [7], attenuators [8], waveguides [9,10] and microlenses [11,12]. The integration of optofluidic technologies with microchannels has paved the way for the development of a variety of optical lab-on-a-chip systems, such as cell sorting [13], microscopy [14], particle analysis [15], surface-enhanced Raman spectroscopy [16] and cavity ring-down spectroscopy [17].…”