Polarization control and enhanced magnetic field sensitivity utilizing surface plasmon polaritons-assisted dual-V-type four-level system

Abstract

We propose a kind of surface plasmon polaritons (SPPs)-assisted dual-V-type four-level composite system used for high-sensitivity weak magnetic field measurement. The SPPs are excited by a D-shaped photonic crystal fiber (PCF) deposited with gold nanowires, and are interacted with the above quantum emitter from the rubidium atomic vapor. In the presence of the external magnetic field, Faraday rotation symmetry is broken due to Zeeman effect, resulting in the polarization plane rotation when a linearly polarized probe field goes through the above quantum emitter. With the help of the coupled field and SPPs, Faraday magneto-optical rotation (MOR) are effectively regulated. The Rabi frequency of the coupled field (Ω c ), quantum interference degree (q), and phase difference (φ) between the applied fields show strong dependence on the MOR angle and magnetic field measurement sensitivity. The simulated results reveal that the maximum MOR angle and magnetic field sensitivity both damp with Ω c expanding and q reducing. The maximum dichroism-independent MOR angle of 89.97° is realized for φ = 0° (180°), and the magnetic field sensitivity of 10.88°/Oe is obtained in the sweeping range of −8.88–8.88 Oe for q = 0.99, being 2.66°/Oe higher than that in the absence of SPPs (q = 0). Most importantly, the output probe field with different polarization forms can be realized by adjusting the φ value. Hence, the proposed device exhibits the potential in the fields of weak magnetic field measurement and polarization control.