The single-photon transmission spectrum under asymmetrical atom–photon couplings (<em>g</em><sub>1</sub> = 0.2, <em>g</em><sub>2</sub> = 0.15) and atom dissipation (1/<em>T</em><sub>a</sub> = 0.1 Ω): (a) Ω<sub>1</sub> = Ω<sub>2</sub> = Ω, 2θ = 2π (red line), 2θ = π (blue line), 2θ = 0.4π (green line); (b) Ω<sub>1</sub> = Ω<sub>2</sub> = Ω, 2θ = 2π (red line), 2θ = π (blue line), 2θ = 0.4π (green line)

<p><strong>Figure 5.</strong> The single-photon transmission spectrum under asymmetrical atom–photon couplings (<em>g</em><sub>1</sub> = 0.2, <em>g</em><sub>2</sub> = 0.15) and atom dissipation (1/<em>T</em><sub>a</sub> = 0.1 Ω): (a) Ω<sub>1</sub> = Ω<sub>2</sub> = Ω, 2θ = 2π (red line), 2θ = π (blue line), 2θ = 0.4π (green line); (b) Ω<sub>1</sub> = Ω<sub>2</sub> = Ω, 2θ = 2π (red line), 2θ = π (blue line), 2θ = 0.4π (green line). The coupling strengths <em>g</em><sub>1</sub> and <em>g</em><sub>2</sub> are in units of <em>V</em><sub>g</sub>.</p> <p><strong>Abstract</strong></p> <p>Based on the symmetric, asymmetric atom–photon couplings and the phase difference between two separated atoms, single-photon transport properties in an optical waveguide coupled with two separated two-level atoms are theoretically investigated. The transmission and reflection amplitudes for the single-photon propagation in such a hybrid system are deduced via a real-space approach. Several new phenomena such as phase-coupled induced transparency, single-photon switches, symmetric and asymmetric bifrequency photon attenuators are analyzed. In addition, the dissipation effect of such a hybrid system is also discussed.</p>