(a) The magnitude and (b) phase of the probe transmission as a function of the (Ω – ω₁)/2π in the two cases, where the two mechanical oscillators have the same frequency (ω₁ = ω₂) and there is only one mechanical oscillator (g₂ = 0). The pump field is tuned to the red sideband of the cavity resonance (Δ_pu = ω₁) with P_pu = 4 μW. Other parameters used are ω_c = 2π × 6.986 GHz, κ = 2π × 6.2 MHz, κ_e = 2π × 4.8 MHz, ω₁ = 2π × 32.1 MHz, γ₁ = γ₂ = γ_m = 2π × 930 Hz, g₁ = 2π × 39 Hz.