Ultrahigh Sensitive Meta-Absorber for Refraction Index Sensor

We propose an ultrahigh sensitive refraction index sensor using metasurface absorber. It exhibits large omnidirectional, polarization-independent, and larger tuning range of resonance in visible wavelength range. By tailoring the geometrical dimensions of metasurface, the resonance can be tuned in the whole visible spectrum. The corresponding full width at halfmaximum is 30 nm. By changing the gap between two metal layers, the tuning range is approximately 100 nm while keeping the absorption intensity above 95%. The proposed device implanted in refraction index sensor exhibits a high-sensitivity of 481.5 nm/RIU.