Laser-rate-equation description of optomechanical oscillators

Area of Science:

• Optomechanics
• Laser Physics
• Condensed Matter Physics

Background:

• Optomechanical oscillators are systems where mechanical and optical properties interact.
• Understanding mechanical amplification is crucial for developing new quantum technologies.
• Existing models may not fully capture the dynamics of self-oscillating optomechanical systems.

Purpose of the Study:

• To develop a theoretical framework describing mechanical amplification in optomechanical oscillators.
• To introduce key parameters for characterizing a "mechanical laser."
• To identify the microscopic origin of optomechanical self-oscillation.

Main Methods:

• Development of a set of laser rate equations tailored for optomechanical systems.
• Introduction of parameters such as gain, stored energy, slope efficiency, and saturation power.
• Theoretical analysis of three-phonon parametric interactions as the enabling mechanism.

Main Results:

• The developed laser rate equations accurately describe mechanical amplification.
• Key parameters for the "mechanical laser" are defined.
• Three-phonon parametric interactions are identified as the microscopic mechanism for self-oscillation.
• The theory demonstrates excellent agreement with experimental data.

Conclusions:

• Optomechanical self-oscillation is fundamentally a "phonon lasing" process.
• Optical pumping generates coherent acoustic phonons, leading to self-oscillation.
• The theoretical framework provides a comprehensive understanding of optomechanical lasing.