Terahertz multichannel microfluidic sensor based on parallel-plate waveguide resonant cavities

We demonstrate a terahertz multichannel microfluidic sensor based on a parallel-plate waveguide geometry with two independent integrated resonant cavities. The resonant frequency of each cavity exhibits an approximately linear dependence on the index of refraction of the material inside the cavity and each cavity is demonstrated to respond independently with no measurable crosstalk. The sensitivities of the two cavities in terms of the change in resonant wavelength per refractive index unit (RIU) are measured to be 1.21 x 10(6) nm/RIU and 6.77 x 10(5) nm/RIU. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4724204]