First observations of an evaporative instability in absorptive dye (Nigrosin) doped water droplets heated by a pulsed Nd:YAlG laser (532 nm) are reported. Measurement of the instability thresholds at different dye concentrations shows an approximate inverse linear dependence on droplet absorption index, suggesting that the instability is caused by superheating of the droplet. The instability may trigger subsequent droplet deformation or or disintegration; however, below a well-defined fluence threshold, complete recovery of the droplet occurs following laser excitation. A qualitative model based on Landau instability theory is used to describe the instability.

• Received 15 January 1991

DOI:https://doi.org/10.1103/PhysRevLett.66.2988