A Model for Fluorescence and Phosphorescence

If you are indoors and reading this document on paper, then the page may be lit by a fluorescent light bulb. The gases inside the bulb absorb high-energy electrons, and then fluoresce, or re-radiate that absorbed energy at a different frequency. The particular gases in common fluorescent bulbs are chosen to be efficient at re-radiating this energy in the visible wavelengths. If you are reading this document on-line, then you’re probably reading it on a cathode-ray tube (CRT). The face of the CRT is lined with phosphors, which absorb the high-energy electrons directed at them, and gradually release that energy over time in the visible band. The two phenomena of fluorescence and phosphorescence are not as common as simple reflection and transmission, but do have an important part to play in the complete description of macroscopic physical behavior that should be modeled by image synthesis programs. This paper presents a mathematical model for global energy balancing which includes these phenomena.