Photo-thermal modeling of laser–phosphor interaction in laser lighting

Abstract

In laser lighting, the heat generated in a phosphor has a great impact on the optical and thermal properties of the phosphor-converted white laser diode (PC-WLD), which is hard to be calculated and measured precisely. We, therefore, propose a photo-thermal modeling of laser–phosphor interaction in laser lighting (PTML) to simulate the illumination energy and temperature distribution of a phosphor. PTML consists of two parts: the modified Monte Carlo method (MCM) and the numerical calculation method based on the three-dimensional heat conduction equation. With full consideration of light scattering, fluorescence reabsorption, and thermal quenching effect, PTML is able to simulate the absorbed energy and temperature distribution inside a phosphor. Experiments with transparent and scattering Ce:YAG phosphor samples are carried out to validate this method. The results show that the difference between the PTML simulated and experimental light transmission energy (laser and fluorescence) is less than 10%. The temperature difference between the PTML simulation and experiment is less than 1.5°C when the laser irradiates on the Ce:YAG single crystal at pump power 1420 mW. Moreover, this method also has potential application in the photo-thermal interaction between bio-tissue and lasers.