title: Cavity-enhanced on-chip absorption spectroscopy using microring resonators.
abstract: We demonstrate on-chip laser absorption spectroscopy using silicon microring resonators integrated with PDMS microfluidic channels. A 100 microm radius microring resonator with Q > 100,000 is used to enhance the interaction length between evanescent light and a cladding liquid. We measure absorption spectra of less than 2 nL of N-methylaniline from 1460 nm to 1610 nm with 1 nm resolution and effective free space path lengths up to 5 mm. This work can help realize a completely on-chip spectroscopy device for lab-on-a-chip applications.
authors.affiliation: School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Arthur
authors.initials: A
authors.lastname: Nitkowski
authors.forename: Long
authors.initials: L
authors.lastname: Chen
authors.forename: Michal
authors.initials: M
authors.lastname: Lipson
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D008904:Miniaturization; D009391:Nephelometry and Turbidimetry / Q000295:instrumentation*; D013057:Spectrum Analysis / Q000295:instrumentation*; D014159:Transducers