Figure 1.

(A) Acoustic wave induced in a plane model of tissue by a short pulse of IR radiation with energy penetration depth in the tissue of 3.5 mm and radiant exposure of 1 J/m². The pulse is assumed to be completely absorbed in the tissue and occurs at t = 0 in this figure. (B) Magnitude spectrum of the waveform. Calculated using Equations (6) and (7) of (3) assuming tissue density of 1,109 kg/m³ and heat capacity of 3,390 J/(kg K). For pulses shorter than the stress relaxation time (≈1 μs) the induced TA wave is essentially independent of the pulse duration.