Figure 3.
Photothermal integral time responses of the 90 nm NP suspension as registered by a continuous probe laser beam during the application of a single pump pulse (532 nm, 0.5 ns): (a) fast heating and slow cooling of the suspension at a pump pulse fluence of 0.08 J/cm2 and below evaporation threshold; (b) bubble-specific signal of the opposite sign that shows the expansion and the collapse, a pump pulse fluence of 0.4 J/cm2 is above the evaporation threshold. The ripple patterns were caused by the probe laser noise, and the x coordinate indicates the time from the moment of exposure of NPs to a pump laser pulse.