Short Term Stability
PhotoFluor II (green) run at 60% output to match 100% power levels of the 120 W metal halide source (gray).
Long Term Stability
PhotoFluor II (green) and 120 W metal halide source (gray) measured at microscope stage over 14 hours. Power meter measured output of a field of fluorescent beads (Tetraspecks) using a 49004 filter set, sampling every 5 seconds. Initial brightness of PhotoFluor II was decreased to match that of the 120 W light source. 20 X Zeiss objective used with a 0.5 ND filter.
The overall decrease in fluorescence intensity reflects the photobleaching of the fluorescence beads over time. Note the sporadic fluxuations of the 120W lamp signal resulting from arc wander and arc flicker (see application note on Stability in Fluorescence Light Sources) as compared to the smooth decay of the PhotoFluor II signal.