Photoacoustic generation for a spherical absorber with impedance mismatch with the surrounding media

J. M. Sun and Bernard S. Gerstman
Phys. Rev. E 59, 5772 – Published 1 May 1999
PDFExport Citation

Abstract

Pressure generation in a spherical absorber due to energy deposition from pulsed lasers is studied. For a variety of conditions, analytical solutions are derived that allow quick computation of exact results. For the special case of identical acoustic impedance, the pressure transient spreads to the surrounding medium by a single compressive pulse followed by a tensile pulse at the end of illumination. For the general case of impedance mismatch, the pressure transient is in the form of a series of dampened compressive and tensile pressure pulses. In this paper both the amplitude ratio and the sign of consecutive pressure pulses are determined analytically, and are shown to be dependent upon the impedance mismatch. For laser pulses of duration much less than the absorber’s characteristic oscillation time, a stress confinement limit is reached for most of the absorber, but a sharp tensile stress in the core region of the sphere is predicted. This region of high stress is defined by r<~rc, and we show that rc is proportional to the laser pulse duration τ0. Upon further shortening of the laser pulse duration, the strength of this tensile stress continues to increase while its spatial distribution is sharpened. This observation has relevance to a number of experiments where laser-induced pressure transients cause the absorber to fracture.

  • Received 13 July 1998

DOI:https://doi.org/10.1103/PhysRevE.59.5772

©1999 American Physical Society

Authors & Affiliations

J. M. Sun and Bernard S. Gerstman

  • Physics Department, Florida International University, University Park, Miami, Florida 33199

References (Subscription Required)

Click to Expand
Issue

Vol. 59, Iss. 5 — May 1999

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review E

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×