Generating strong mechanical squeezing via combined squeezed vacuum field and two-tone driving

TL;DR

This work tackles robust mechanical squeezing in cavity optomechanics by integrating two-tone driving with squeezed-vacuum field injection. The authors develop a Gaussian-state framework, linearize the Hamiltonian to obtain an effective interaction, and analyze the covariance dynamics to quantify squeezing. They show that the squeezed vacuum transfers noise suppression to the mechanical mode, enabling both position and momentum squeezing with a $2 ext{D} ext{pi}$-periodic dependence on the squeezing phase $ heta$, and they reveal a strong nonlinear enhancement of squeezing with the parameter $r$. The scheme achieves up to $22.26$ dB of position squeezing and exhibits remarkable robustness against cavity dissipation and thermal noise, reducing the stringent parameter-matching requirements of previous approaches and offering flexible, phase-controlled squeezing for quantum information tasks.

Abstract

We propose a novel scheme for generating mechanical squeezed states based on the combined mechanism of a two-tone driving and a squeezed vacuum field. This innovative approach achieves a remarkable improvement in mechanical squeezing performance across the entire range of red/blue detuning ratios. Our study reveals that the squeezed vacuum field not only induces position squeezing of the mechanical oscillator but also facilitates momentum squeezing through phase matching. Moreover, the total squeezing degree exhibits nonlinear enhancement with the increasing of squeezing parameter $r$. The mechanical squeezed state exhibits a $2π$-periodic dependence in relation to the squeezing phase $θ$, offering experimental implementation with a high degree of operational flexibility. Notably, the scheme exhibits strong robustness against cavity dissipation and environmental thermal noise, substantially relaxing the strict parameter-matching requirements inherent in conventional approaches.

Figures (6)

• Figure 1: Schematic diagram of the system model. The optomechanical system consists of a mechanical oscillator and an optical cavity. The optical cavity is driven by two-tone detuned lasers, one red-detuned and one blue-detuned, and an appropriate squeezed vacuum field is also applied to the optical cavity.
• Figure 2: Panels (a) and (b) show the position squeezing and momentum squeezing of the mechanical oscillator, respectively, as functions of the phase $\theta$ under different squeezing parameters $r$. The system parameters are set as: $\kappa=0.1\omega_m$, $g_0=10^{-4}\omega_m$, $\gamma_m=10^{-6}\omega_m$, $g_-=0.01\omega_m$, $g_+=0.2g_-$, $n_m^{\text{th}}=0$. The black dashed line indicates the 3 dB squeezing limit.
• Figure 3: Panel (a) shows the position squeezing of the mechanical oscillator as a function of the ratio $g_+/g_-$ under different squeezing parameters $r$. Panel (b) illustrates the dependence of the total squeezing degree $S$ on the phase $\theta$ under different squeezing parameters $r$. The other parameters are the same as those used in Fig. \ref{['fig:2']}.
• Figure 4: The variation of Wigner function of the mechanical oscillator in phase space $\delta{Q}$ and $\delta{P}$ for different squeezing phases $\theta$. The squeezing parameter is set as $r=1$, while the other parameters are the same as those in Fig. \ref{['fig:2']}.
• Figure 5: The combined effect of the red/blue detuned ratio $g_+/g_-$ and the squeezing parameter $r$ on the squeezing degree of position $S(Q)$. The parameters are the same as those used in Fig. \ref{['fig:2']}.