(color online) Transmission spectrum of inner circle (a), surface current distributions at (b) φ = 0°, (c) φ = 30°, (d) φ = 60°, and (e) φ = 90°, and electric field distributions at (f) φ = 0°, (g) φ = 30°, (h) φ = 60°, and (i) φ = 90°.