We present and validate a novel route to directly probe the dissipative optomechanical coupling in a balanced homodyne detection scheme. The ratio between dissipative and dispersive coupling is determined as G κ e / G ω ≈ − 0.007 ± 0.001 .

We present a homodyne detection scheme to reliably measure the dissipative coupling in optomechanical systems. Our method is validated on silicon devices yielding G κ e /Gω = −0.007 ± 0.001.

We demonstrate dissipative optomechanical transduction and backaction in coupled nanobeams. Compared to previous demonstrations, our system corresponds to a hundredfold increase in mechanical frequency and displays a record-high dissipative optomechanical coupling.