The investigation of light-matter interaction has had growing interest in the field of photonics. In particular, metalinsulator-metal (MIM) sensors are of interest owing to their high sensitivity compared to conventional sensor made by a single metal layer. The high resolution and low concentrations detection is a result of the sharp resonance of the surface plasmon polariton waveguide hybrid mode at the Au/water interface supported by MIM structures. In this context, we have implemented experiments and theoretical simulations to estimate the enhancement of the sensitivity of metal-insulatormetal sensors. By changing the refractive index of an aqueous solution of glucose, we found that the use of a metalinsulator-metal stack improves the figure of merit of the sensor 7.5 times compared to that of a conventional surface plasmon resonance sensor.