Fig. 2: Theoretical demonstration of birefringence-sensitive topological transition.
From: Precise detection of tiny birefringence with accuracy reaching 10−11 level
a–c Harmonic Rabi oscillations of a photonic state between the pseudo spin up and spin down components, represented as S2(z) = ∣ΦR∣2 − ∣ΦL∣2. These harmonic oscillations are achieved with an initial state [located at (θ, φ) = (π/2, π/2)] carried by a subwavelength BG envelope (envelope parameter r0 = 130 nm), in different conditions of birefringence: a n = 0; b Δn = 10−11; and c Δn = 10−10. For a given coupling length L = 240 μm, the output spin-orbit state exhibits a prominent birefringence-sensitive phase shift indicated by points c2, c3, and c4, with respect to the incident one (point c1). The resultant Rabi oscillation period is calculated as: a Λ = 60.00 μm; b Λ = 58.43 μm; and c Λ = 56.84 μm. d–g Inhomogeneous polarization distributions of the photonic state at the initial (d, input point c1) and final (e, f, and g, output points c2, c3, and c4) positions of the crystal. h–k Inhomogeneous phase distributions of the photonic state at positions corresponding to (d–g), featuring OAM variations.
