Because of its compactness and high efficiency, the image furnace using ellipsoid mirrors to focus infrared heating from lamps has widely been used in floating-zone (FZ) crystal growth. However, little research has been reported on modeling energy distribution in such a system. In this paper, a simple model considering direct and indirect radiation from the lamps is presented. This model is consistent with the point-source model as the lamp size is diminished. The effects of lamp size, shape, orientation, and defocusing are discussed. The model is further integrated with a three-dimensional thermal-capillary model. Therefore, the temperature distribution and the zone shape of the sample during FZ growth in the furnace can be estimated. Temperature measurements of a graphite rod in a mirror furnace were also conducted to validate the global model.
