  Ultrathin microscale resistive thermometers are of key value to many
applications. Here we have fabricated a laser machined 50 ${\mu}$m wide and 50
nm thick serpentine Pt thin film sensor capable of sensing temperatures up to
650 ${^\circ}$ C over multiple heating and cooling cycles. Various materials
and associated processing conditions were studied, including both sapphire and
silica as transparent substrates, alumina and TiO2 as adhesion layers, and
lastly alumina and silicon oxide as capping layer. In-situ resistance
monitoring helps to verify the multi-cycle stability of the sensor and guide
the optimization. 10 ${\mu}$m sized sensors can be laser machined but will not
survive multiple heating and cooling cycles. We demonstrate that the sensors
with amorphous Ge thin layers can also repeatably measure temperatures up to
650 ${^\circ}$ C. It is anticipated that this sensor can be used for fast and
high spatial resolution temperature probing for laser processing applications.
