Fast calculation of pulsed photoacoustic fields in fluids using k-space methods

Area of Science:

• Acoustics
• Biomedical Optics
• Computational Physics

Background:

• Photoacoustic imaging relies on understanding pressure wave propagation.
• Accurate and efficient numerical models are crucial for simulating photoacoustic fields.
• Existing models can be computationally intensive.

Purpose of the Study:

• To present two novel numerical models for calculating time-dependent photoacoustic pressure fields.
• To develop fast and accurate computational tools for photoacoustic wave propagation.
• To enable detailed analysis of photoacoustic phenomena, including radiation patterns and acoustic vectors.

Main Methods:

• Frequency-wavenumber (k-space) implementations for efficient computation.
• Development of Model I for visualizing 3D wave field evolution.
• Development of Model II for simulating array measurements and calculating time series.
• Utilizing the fast Fourier transform (FFT) for computational speed.
• Separate calculation of propagating and evanescent wave components.

Main Results:

• Model I provides instantaneous 3D pressure field visualization.
• Model II achieves up to 50x speed improvement for time series calculations compared to existing models.
• Model II can compute far- and near-field radiation patterns.
• Models were validated against analytic solutions and established numerical methods.

Conclusions:

• The presented numerical models provide fast, accurate, and versatile tools for photoacoustic field prediction.
• Model II offers significant speed advantages for simulating photoacoustic array measurements.
• These models can be extended to calculate acoustic intensity vectors and incorporate detector responses.