Abstract

Acoustic transients induced by short laser pulses in biological tissues carry specific information about axial light and temperature-field distributions, absolute values of elastic and recoil pressure, and stress wave propagation (see Fig. 1). Time-resolved detection of laser-induced stress transients with a broad-band lithium niobate acoustic transducer allows absolute measurements of initial thermoelastic stress distributions in turbid and layered media. Optical properties of biological tissues can be determined from stress magnitudes and exponential slopes. Laser ablation causes a recoil momentum transfer upon material ejection. Measurements of recoil stress kinetics helps to clarify ablation mechanism and to determine optimal laser parameters for efficient laser ablation with minimal thermal and mechanical injury to adjacent tissue layers.

© 1994 IEEE