Levitated Optomechanics Squeeze Phonon Lasers by 3.15 dB

Researchers have achieved a 3.15 ± 0.35 decibel squeeze in a thermomechanically driven phonon laser using a levitated optomechanical system, a result previously unattained for classical squeezing of phonon lasers. The team, led by Guangzong Xiao, induced non-adiabatic frequency shifts with a pulse-modulated trapping laser, which reduced noise in the mechanical oscillator and demonstrates an advance in controlling these systems. This approach squeezed not only the fundamental mode but also the second-harmonic mode of the phonon laser, revealing a capability for concurrent coherent control of multi-mode phonon lasers. This work, the first to demonstrate a squeezed nonlinear phonon laser with a larger mass under low vacuum, provides a promising platform for precision metrology and exploration of nonlinear phononics.

This level of squeezing, a reduction of noise in a specific measurement parameter, had not previously been achieved for classical squeezing of phonon lasers, mechanical counterparts to optical lasers. The team, led by Guangzong Xiao, utilized a levitated optomechanical system, suspending a microscale sphere to isolate it from external disturbances and facilitate precise manipulation. Central to this achievement was the implementation of a pulse-modulated trapping laser, which induced non-adiabatic frequency shifts, allowing for the squeezing of the fundamental-mode phonon laser. This capability opens avenues for exploring nonlinear phononics, the study of sound waves in solids, and potentially harnessing the system for applications requiring high precision, such as advanced metrology. The work was supported by the Quantum Science and Technology-National Science and Technology Major Project (2024ZD0301000), among other funding sources.

Researchers have demonstrated an advance in controlling mechanical oscillators by achieving squeezing in a thermomechanically driven phonon laser, a mechanical counterpart to optical lasers; this represents the first instance of classical squeezing of phonon lasers. The team, working with a levitated optomechanical system featuring a microscale sphere, reports a 3.15 ± 0.35 dB squeeze, a reduction in noise below the standard quantum limit, previously unattainable for classical phonon lasers. This feat was accomplished through non-adiabatic frequency shifts induced by a pulse-modulated trapping laser. The ability to manipulate multiple modes concurrently allows for more complex and nuanced control over mechanical oscillations. The researchers gratefully acknowledge assistance from Qian Zhang at Hunan Normal University and Zijian Feng and Yutong He at the National University of Defense Technology, highlighting the collaborative nature of this research.