High-Performance Guided Mode Resonance Optofluidic Sensor

This paper reports on the high performance of a thick-waveguide guided mode resonance (GMR) sensor. Theoretical calculations revealed that when light incidents on the grating and excites the negative first-order diffraction order, by increasing the waveguide thickness, both a high sensitivity and high figure of merit (FOM) can be obtained. Experimentally, we achieved a sensitivity of 1255.78 nm/RIU, a resonance linewidth of 0.59 nm at the resonance wavelength of 535 nm, an FOM as high as 2128 RIU^-1, and a detection limit as low as 1.74 × 10^-7 RIU. To our knowledge, this performance represents the highest comprehensive level for current GMR sensors. Additionally, the use of a microfluidic hemisphere and polymer materials effectively reduces the liquid consumption under oblique incidence and the fabrication cost in practical application. Overall, the proposed GMR sensor exhibits great potential in label-free biosensing.