Use of TRMPS probing means that it is possible to observe each individual T-jump in the pump burst with nanosecond time resolution, allowing the evolution of the sample to be observed at each successive temperature caused by each laser pulse of the burst (Figure ). Fitting of the sample cooling kinetics for each pulse shows the fast bi-exponential decay constant increasing from ca. 1 to ca. 3 ms over the course of the burst process. This can be attributed to the heated volume of the sample enlarging with the repeated laser pulses relative to the laser-pumped volume. Simulations indicate that the full-width at half maximum of the radial temperature distribution increases from 36 μm after a single pulse to ca. 80 μm after a 50-pulse burst (ESI, Section 19). The subsequent reduction in thermal gradient in the radial direction leads to slower cooling.