photodiode quantum efficiency, $Q_o$, $g^{(2)}$, and waveguide transmission losses. Both $G_2$ and $S_{x^{2}}$ assume there is no backaction and the device is operating in the sideband-unresolved regime [@ref:aspelmeyer2014co].

Figures \[figureFive\](a,b) show the thermally driven $S_{P}^{(2)}(\omega)$ of the sliding resonance at an operating temperature of 300 K, and indicate that it can be observed above technical noise. The signal strength varies with $L$ and the mechanical detuning $\omega/\omega_m$; traces in Fig.’s \[figureFive\](a,b) correspond to signal for $L$ = 50 $\mu$m in their respective spectrographs $S_{P}^{(2)}(\omega,L)$, which are also shown. These spectra assume reasonable experimental parameters: $P_i$ = 100 $\mu$W chosen so as to not saturate the detector, the input laser detuning from the nanocavity resonance set to maximize $G_2$, and either relatively low $Q_o$ = $4.0~\times~10^3$ and $Q_m$ = $10^2$ (Fig.’s \[figureFive\](a)) or attainably high $Q_o$ = $4.0~\times~10^4$ and $Q_m$ = $10^5$ (Fig.’s \[figureFive\](b)). The power spectrum is strongest at $\omega = 0$ and $\omega/\omega_m$ = $\pm$ 2, with the latter being of interest in practical experiments so as to minimize the influence of $1/\omega$ technical noise not considered here. The signal generally increases with $Q_o$ and $Q_m$, and the FWHM (full-width, half-maximum) of the peaks narrows with increasing $Q_m$. As 