Label-free water sensors using hybrid polymer-dielectric mid-infrared optical waveguides. Academic Article uri icon


  • A chip-scale mid-IR water sensor was developed using silicon nitride (SiN) waveguides coated with poly(glycidyl methacrylate) (PGMA). The label-free detection was conducted at =2.6-2.7 m because this spectral region overlaps with the characteristic O-H stretch absorption while being transparent to PGMA and SiN. Through the design of a hybrid waveguide structure, we were able to tailor the mid-IR evanescent wave into the PGMA layer and the surrounding water and, consequently, to enhance the light-analyte interaction. A 7.6 times enhancement of sensitivity is experimentally demonstrated and explained by material integration engineering as well as waveguide mode analysis. Our sensor platform made by polymer-dielectric hybrids can be applied to other regions of the mid-IR spectrum to probe other analytes and can ultimately achieve a multispectral sensor on-a-chip.

published proceedings

  • ACS Appl Mater Interfaces

author list (cited authors)

  • Lin, P. T., Giammarco, J., Borodinov, N., Savchak, M., Singh, V., Kimerling, L. C., ... Agarwal, A.

citation count

  • 18

complete list of authors

  • Lin, Pao Tai||Giammarco, James||Borodinov, Nikolay||Savchak, Mykhailo||Singh, Vivek||Kimerling, Lionel C||Tan, Dawn TH||Richardson, Kathleen A||Luzinov, Igor||Agarwal, Anu

publication date

  • June 2015