Entanglement between the cavity field and the mechanical mirror, and the dashed-dotted, dashed, and solid lines correspond to G = 0, 0.8κ, and 0.9κ, respectively. For all plots, the parameters are L = 5 mm, m = 20 ng, ω_m = 2π × 10⁷ Hz. The laser has wavelength λ = 810 nm and power = 10 mW, the mechanical quality factor Q′ = ω_m/γ_m = 6700.