title: Fabrication and testing of planar chalcogenide waveguide integrated microfluidic sensor.
abstract: We have fabricated and tested, to the best of our knowledge, the first microfluidic device monolithically integrated with planar chalcogenide glass waveguides on a silicon substrate. High-quality Ge(23)Sb(7)S(70) glass films have been deposited onto oxide coated silicon wafers using thermal evaporation, and high-index-contrast channel waveguides have been defined using SF(6) plasma etching. Microfluidic channel patterning in photocurable resin (SU8) and channel sealing by a polydimethylsiloxane (PDMS) cover completed the device fabrication. The chalcogenide waveguides yield a transmission loss of 2.3 dB/cm at 1550 nm. We show in this letter that using this device, N-methylaniline can be detected using its well-defined absorption fingerprint of the N-H bond near 1496 nm. Our measurements indicate linear response of the sensor to varying N-methylaniline concentrations. From our experiments, a sensitivity of this sensor down to a N-methylaniline concentration 0.7 vol. % is expected. Given the low-cost fabrication process used, and robust device configuration, our integration scheme provides a promising device platform for chemical sensing applications.
authors.forename: Juejun
authors.initials: J
authors.lastname: Hu
authors.forename: Vladimir
authors.initials: V
authors.lastname: Tarasov
authors.forename: Anu
authors.initials: A
authors.lastname: Agarwal
authors.forename: Lionel
authors.initials: L
authors.lastname: Kimerling
authors.forename: Nathan
authors.initials: N
authors.lastname: Carlie
authors.forename: Laeticia
authors.initials: L
authors.lastname: Petit
authors.forename: Kathleen
authors.initials: K
authors.lastname: Richardson