Squeezed Phonon Lasing via Floquet-Controlled Solid-State Defects

Abstract

We propose a general Floquet-engineered scheme for squeezed phonon lasing that enables a continuous crossover from conventional phase-diffused phonon lasing to phase-locked squeezed phonon lasing. Our system consists of two pairs of periodically driven spins--a primary pair and an ancilla pair--coupled to a single mechanical mode. While the underlying mechanism applies generally to such spin-mechanical systems, we focus on a solid-state implementation based on color centers embedded in a circular hexagonal boron nitride (hBN) membrane. We show that the primary spins provide mechanical gain, whereas the ancilla pair engineer a dissipative channel for the Bogoliubov mode, thereby stabilizing robust steady-state squeezed phonon lasing. We support these findings through a comprehensive steady-state analysis of the lasing threshold, mechanical occupation, emission spectrum, and second-order correlations. Remarkably, we demonstrate that Floquet engineering intrinsically induces phase locking while enabling controllable quadrature squeezing, providing a simple and versatile route toward squeezed lasing in solid-state spin-mechanical platforms.

20 pages, 9 figures. We would be grateful for any comments or suggestions