Spurious-sound-free measurement of parametric acoustic array using optical interferometry

Area of Science:

• Acoustics
• Optical Physics
• Signal Processing

Background:

• Parametric acoustic arrays (PAA) are often measured using microphones.
• Microphone nonlinearity generates spurious sound, interfering with accurate PAA measurements.

Purpose of the Study:

• To propose a spurious-sound-free measurement method for PAA.
• To validate the proposed method against numerical simulations.

Main Methods:

• Utilizing optical interferometry for PAA measurement.
• Employing Gaussian beam expansion to enhance optical measurement.
• Comparing results with finite element method (FEM) numerical simulations.

Main Results:

• The proposed optical interferometry method successfully measured the demodulated audio sound.
• No spurious sound effects were observed in the measurements.
• Comparison with FEM simulations confirmed the accuracy of the proposed method.

Conclusions:

• Optical interferometry provides a robust solution for spurious-sound-free PAA measurement.
• This method overcomes the limitations of traditional microphone-based measurements.
• Accurate PAA characterization is achievable without acoustic noise interference.