The absorption Re[ɛ_T] as a function of (δ − ω_b)/ω_b for identical and different mechanical resonator frequencies: ω_d = ω_b (black solid line), ω_d = 1.1ω_b (red dashed line), ω_d = 0.9ω_b (blue dotted-dashed line). The other parameters are the same as those in Fig. 2.