A Laser beam is applied on a sample of phosphor powder {1.5% Dysprosium (Dy) + 0.5% Erbium (Er): Yttrium-Aluminum-Garnet (YAG)} with three laser power ratios (LPR) namely 60%, 62% and 100%. The sample is maintained in a furnace with temperatures varying from room temperature up to 1825 ˚C. The excited phosphor exhibits phosphorescence. The emitted light or phosphorescence is collected by a spectrometer that analyses the intensity of the collected spectrum and the wavelengths. This testing may prove that temperature measurements are possible in this environment, given proper selection of the emission wavelength and temperature range. Optimization of the optical efficiency is necessary for extended temperature range. Application for surface temperature measurements in combustion systems is under preparation. Measurements will be carried out utilizing binder material with phosphor powder