Patent ID: 8195014

Claim:
A sensor comprising: a substrate comprising a flow channel for conveying a fluid, wherein the flow channel comprises a first region; a laser for providing light having a spectral bandwidth that includes a first wavelength; and a waveguide resonator mirror, wherein the waveguide resonator mirror comprises a first optically resonant element, and wherein the first optically resonant element is located within the first region, and wherein the first optically resonant element is optically resonant for the first wavelength when the fluid in the first region has a first refractive index, and further wherein the first optically resonant element is optically resonant for a second wavelength when the fluid in the first region has a second refractive index; wherein the laser provides the light to the waveguide resonator mirror, and wherein the laser receives the first wavelength from the waveguide resonator mirror when the fluid in the first region has the first refractive index.