Excitation power dependent optical temperature behaviors in Mn 4+ doped oxyfluoride Na 2 WO 2 F 4

is achieved at 193 K with the intensity ratio of anti-Stokes bands to the ZPL under 488 nm excitation by a Xenon lamp. This work presents a new method to realize optical thermometry at low temperature by controlling the intensity ratio of the anti-Stokes bands to the ZPL.