The generated magnitude of quadrature squeezing in a cavity-coupled ensemble, which is continuously driven using a coherent off-axis field, is theoretically explored. Using a truncated set of equations of motion derived from a Dicke Hamiltonian, steady-state quadrature squeezing of the cavity field is numerically calculated to approach a limit of $-3\mathrm{dB}$, while frequency-modulated quadrature squeezing approaches a limit of $-14\mathrm{dB}$, in the absence of pure dephasing and as a function of the ensemble's size and detuning. The impact of pure dephasing on steady-state quadrature squeezing is shown to be mitigated by increased detuning of the driving field, while frequency-modulated squeezing is only shielded in a regime where the cumulative coupling and driving rates are in excess of the pure-dephasing rate. Spin-squeezed entanglement is also calculated to occur simultaneously with weakly driven frequency-modulated quadrature squeezing.

• Received 31 July 2020
• Revised 21 December 2020
• Accepted 4 January 2021

DOI:https://doi.org/10.1103/PhysRevA.103.023701