Precise measurement of laser power using an optomechanical system

Area of Science:

• Optomechanics
• Laser Physics
• Precision Measurement

Background:

• Accurate laser power measurement is crucial for scientific research and technological applications.
• Traditional methods may face limitations in precision or scope.
• Optomechanical systems offer a sensitive platform for detecting minute forces, like radiation pressure.

Purpose of the Study:

• To develop and demonstrate a novel optomechanical method for precise laser power measurement.
• To quantify the number of photons in a continuous-wave laser beam.
• To achieve measurement uncertainties below one percent.

Main Methods:

• Utilizing an optomechanical system comprising a suspended mirror acting as a mechanical oscillator.
• Coupling the mirror's motion to the radiation pressure exerted by an amplitude-modulated laser beam.
• Employing a Michelson interferometer to precisely measure the mirror's displacement.
• Calibrating the system to relate displacement to incident laser power.

Main Results:

• Demonstrated a prototype experiment with a 25 mg suspended mirror.
• Successfully measured laser-induced mirror displacement due to radiation pressure.
• Achieved precise measurement of the number of photons in the laser beam.
• Attained laser power measurement uncertainty of less than one percent (1σ).

Conclusions:

• The proposed optomechanical method provides a highly precise approach for laser power determination.
• This technique accurately quantifies photon numbers by measuring radiation pressure effects.
• The demonstrated prototype validates the feasibility and effectiveness of the method for high-accuracy measurements.