Self-assembling and packaging of microbottle resonators for all-polymer lab-on-chip platform

An integrated full polymeric sensing platform composed by a self-assembled bottle microresonators packaged with planar waveguide in a stable structure is presented. Microbottles made of SU-8 resist and NOA resins have been fabricated and characterized. The interrogation system is constituted by evanescently coupled planar waveguide fabricated in SU-8 on polymethyl methacrylate substrate. A simple and effective method for the packaging of the microbottle has been adopted. It provides high mechanical stability to avoid surrounding disturbance able to affect the coupling efficiency between the resonator and the waveguide. The choice of polymers as fabrication material enables the use of this method for low-cost lab-on-chip production. The viability of the platform has been demonstrated via refractometric sensing establishing a bulk sensitivity of 120 nm per refractive index unit.