  We report direct and absolute temperature measurements in a diode-end-pumped
Yb:YAG crystal, using a calibrated infrared camera, with a 60-$\mu$m spatial
resolution. The heat transfer coefficient has been measured, for the first time
to our knowledge, with four different types of thermal contact (H = 0.25, 0.28,
0.9 and 2.0 for bare contact, graphite layer, indium foil and heat sink grease
respectively). The dynamics of thermal effects is also presented.
