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Transient heat fluxes in cutting-edge computing systems, electromagnetic switches, and diode-pumped lasers can exceed 50 MW/m2, which is nearly the heat flux radiated by the Sun. To manage extreme thermal loads, the State-of-the-Art is to boil and evaporate liquid coolants on micro- and nano-structured heat sinks. This work demonstrates the application of laser-scanning fluorescence thermography to identify the spatiotemporal limits of local, transient hot-spot cooling with impinging pulsed micro-jets and sprays. The laser-scanning fluorescence thermography measurements are based on the fluorescence of PS microspheres and quantum-dot thin-films deposited on FTO-glass heater substrates. The fluorescence-based thermometers are subsequently coated with either Hafnium (Hf) or Titanium (Ti) metal thin-films, serving as both protective coatings and the heater surfaces at near critical heat flux conditions. This work also discusses the fabrication procedure of the fluorescence heater/thermometers with micro-mesh heater surfaces and the corresponding pulsed-jet-boiling data via IR thermography.