Figure 3: Coherent response.
From: Quantum electromechanics on silicon nitride nanomembranes
(a) Schematic of the two-tone electromagnetically induced transparency (EIT) spectroscopy measurement. (b) Measured (blue points) probe spectra for different drive powers (P0=1 mW), all with a fixed drive detuning of Δr,d=ωm=4.815 MHz. Each spectrum is offset by −16.5 dB for better visibility. Fits to measured spectra using equation (2) are shown as solid red curves. Inset shows a zoomed-in view of the lowest power measurement with a mechanical linewidth of γm/2π=8 Hz. (c) Extracted system parameters (symbols) as a function of drive power using equation (2) to fit the measured spectra (P0=1 mW). Error bars correspond to a 95% confidence interval in the fit to the measured spectra. (d) Mechanical linewidth γm (top) and the mechanical frequency shift δωm due to the optical spring effect (bottom) versus drive detuning Δr,d at a fixed intra-cavity drive photon number. Shown are the fit values from the measured probe spectra for two different fridge temperatures, Tf=11 mK (blue circles) and Tf=114 mK (red circles). The drive photon number at Tf=11 mK (Tf=114 mK) is equal to nd=2,350 (5,980). The solid line curves are a fit to the damping and spring shift using a radiation pressure back-action model as per ref. 42.
