Light recycling characteristics of ultra-bright lamps

Abstract

The brightness of many lamps, and hence the attainable power density at the target application, can be enhanced by recycling light back into the lamp's radiant zone. We report measurements of the effectiveness, spectral characteristics and modified plasma brightness maps that result from light recycling with a specular hemispherical mirror in commercial 150 W ultra-bright Xenon short-arc discharge lamps. Lamp brightness can be increased by up to 70% for certain spectral windows and plasma arc regions. However, lamp geometry reduces overall light recycling effectiveness to about half this value. This study was motivated by biomedical and high-flux furnace applications where the full spectrum of lamp emissions can be exploited, heightened brightness allows a broader range of procedures, and the design of the affiliated optical systems is contingent upon how plasma radiometric characteristics are altered by photon regeneration.