  We study self-propulsion of a half-metal coated colloidal particle under
laser irradiation. The motion is caused by self-thermophoresis: i.e. absorption
of laser at the metal-coated side of the particle creates local temperature
gradient which in turn drives the particle by thermophoresis. To clarify the
mechanism, temperature distribution and a thermal slip flow field around a
micro-scale Janus particle are measured for the first time. With measured
temperature drop across the particle, the speed of self-propulsion is
corroborated with the prediction based on accessible parameters. As an
application for driving micro-machine, a micro-rotor heat engine is
demonstrated.
