Ultraviolet Characterization of Integrating Spheres
Ping-Shine Shaw, Zhigang Li, Uwe Arp, Keith R. Lykke
We have studied the performance of integrating spheres in the ultraviolet (UV) with wavelengths as short as 200 nm. Two techniques were used for this study; first, the spectral throughput of an integrating sphere irradiated by a deuterium lamp was analyzed by a spectrometer. Second, a laser beam was directed into an integrating sphere and spectrally dispersed Laser Induced Fluorescence (LIF) was studied. Significant absorption and fluorescence features occur in the UV from an integrating sphere which are attributed to the contamination of the integrating sphere. We demonstrate that integrating spheres are easily contaminated by environmental pollutants such as Polycyclic Aromatic Hydrocarbons (PAH) emitted from engine exhaust. Baking of the contaminated integrating sphere can reverse some but not all of the effects caused by contaminants. The implication for using integrating spheres for UV purposes.