Observation of Aulter-Townes Splitting in Subwavelength Grating Metamaterial Ring Resonators

Subwavelength grating metamaterial (SGM) waveguide is typically treated as a homogeneous medium without considering the intra-waveguide reflection. However, this approximation is not always valid, especially in resonators. Inthis paper, we show that the reflection induced mutual coupling between the clock-wise (CW) and counter clock- wise(CCW) resonant modes in subwavelength grating metamaterial waveguide ring resonator (SGMRR) breaks the degeneracy of the two modes, leading to the formation of Autler-Townes splitting (ATS). This phenomenon could beleveraged to improve the detection limit of SGMRR based sensors.