Operando high speed near infrared imaging during laser sintering of nanoparticles for time and space resolved temperature measurements

A high-speed camera equipped with a near-infrared (NIR) microscope optic is employed for spatially resolved NIR thermal imaging during laser sintering. The device enables operando temperature measurements with a temporal resolution less than 1 ms and a spatial resolution better than 10 μm. The feasibility for in situ temperature measurements is demonstrated for resonant laser sintering of TiO2 nanoparticles. The temperature range is calibrated at a framerate of 1,069 frames per second (fps) using a TiO2 reference sample. The laser sintering process is observed at framerates of up to 15,969 fps. The resulting microstructure of the TiO2 sample is analyzed by scanning electron microscopy (SEM) and interpreted in view of the recorded sintering temperature profiles.