Overview of Advances in Light Sources
Current efforts at the Lawrence Berkeley Laboratory to improve the operational efficiency of fluorescent lamps are based upon novel techniques intended to reduce internal resonance radiative transport losses. Such losses have been associated with entrapment of resonance radiation in the optically thick positive column of the mercury vapor discharge. Two promising techniques for entrapment reduction are provided respectively to selective mercury isotope enrichment and by the broadening of the hyperfine structure (hfs) of the resonance line λ2537 via the Zeeman effect. These techniques have, thus far, led to fluorescent lamp UV production efficiency enhancements, respectively of about 6.8% and 7%.
Additional efforts to improve HID sources are in progress. Interesting metallic halides have been combined with electrodeless arc technology to produce a laboratory discharge system operating with an efficacy exceeding 170 lumens per watt, and a color rendering index (CFI) of 52.