Nonlinear optomechanically induced frequency locking and its application to room temperature mass sensing

Area of Science:

• Nonlinear optomechanics
• Cavity optomechanical systems
• Nanoscale sensing

Background:

• Optomechanical systems couple light and mechanical motion.
• Precise mass sensing is crucial for various scientific and technological applications.
• Existing methods face limitations in sensitivity, operating range, or temperature dependence.

Purpose of the Study:

• To propose and demonstrate a mass sensing mechanism based on nonlinear optomechanics.
• To achieve ultra-high sensitivity for detecting tiny mass changes.
• To develop a robust mass sensor operable at room temperature with a wide dynamic range.

Main Methods:

• Utilizing a two-tone laser pump to drive a cavity optomechanical system into a specific nonlinear dynamical regime.
• Correlating mechanical oscillations with sidebands of the cavity field.
• Measuring changes in sideband intensities after adding a nanoparticle of unknown mass (δm).
• Employing an additional single-tone laser field to enhance sideband signals in membrane-in-the-middle systems.

Main Results:

• The mechanical oscillation frequency is locked to the system's intrinsic frequency.
• The change in sideband amplitude is linearly proportional to the added mass (δm) within a certain range.
• Achieved ultra-high mass sensitivity (δm/m ~ 10^-11) with a membrane resonator.
• Demonstrated a wide operational range (7-8 orders of magnitude).
• The dynamical pattern shows robustness against thermal noise.

Conclusions:

• The proposed nonlinear optomechanical mass sensor offers precise and ultra-high sensitivity detection of mass.
• The sensor's robustness against thermal noise allows for room-temperature operation.
• This technology holds significant potential for advancements in nanoscale metrology and sensing.