Subnanosecond probing of the ablation of soft plaque from arterial wall by 308 nm pulses delivered through a fiber

Ablation and etching in air by pulsed, ultraviolet (308-nm) laser radiation of the surface of a sample of soft plaque attached to the arterial wall were probed by pulses of visible laser radiation (596 nm; <1 ns FWHM). The ultraviolet radiation was delivered to the sample by an optical fiber 600 μm in diameter. The results of the probing were recorded photographically. Ablation and etching in air of the intimal wall by laser pulses at the same wavelength were also probed in the same manner for comparison. When the fiber tip was 0.5 mm above the sample surface, the ablation that was caused by the laser pulse was readily seen as a blast wave of expanding gases that was followed by the ejection of solid particulates