Single Step Fabrication of an Integrated Polymeric Waveguide

Optical detection is one of the most common methods of detection in microfluidic systems[1]. An optical waveguide is a viable means of delivering optical energy from one point to another in a microfluidic chip. A waveguide typically consists of two optically transparent materials with the material of higher refractive index forming a core and a material with lower refractive index forming the cladding. Such a structure is commonly seen in optical fibers. Different methods exist for integrating optics into a microfluidic chip – glass optical fibers can be embedded into polymer chips or polymeric waveguides may be patterned in parallel with the microfluidic chip[2]. These solutions require multi-step processes, different polymers and a lot of time to fabricate. In this paper we present a low cost, disposable, easily to fabricate optical waveguide directly integrated into a polymer microfluidic chip. Poly methyl methacrylate (PMMA) has been used to fabricate the waveguide and its design consists of a micro-fluidic channel with a cross-section as illustrated in Fig 1a. A thin layer of polymer forms th