title: Highly sensitive refractive index sensing by fast detuning the critical coupling condition of slot waveguide ring resonators.
abstract: We experimentally investigate refractive index sensing in silicon slot waveguide ring resonators by the detection of the giant shift of the ring transmission spectrum envelope enabled by the following specific conditions: the slot waveguide cross section as well as the ring couplers have been designed to lead to a V-shaped microring resonator spectrum modulated by the classical frequency comb and exhibiting quality factor peaks of 2000-6000 around λ=1.5  μm. By tracking the spectrum envelope wavelength shift, sensitivity up to S=1,300  nm per refraction index unit (RIU) is reported when the slots are filled by liquids with refraction index values close to 1.33.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Zhang
authors.forename: Samuel
authors.initials: S
authors.lastname: Serna
authors.forename: Xavier
authors.initials: X
authors.lastname: Le Roux
authors.forename: Laurent
authors.initials: L
authors.lastname: Vivien
authors.forename: Eric
authors.initials: E
authors.lastname: Cassan
mesh_terms: D055096:Optical Devices; D012031:Refractometry / Q000295:instrumentation*; D013997:Time Factors