Comparison of LED source with mercury arc lamp at two time scales of particular interest.

<p><b>A.</b> Fluctuations in the output of the LED source (black) and the mercury arc lamp (gray) in a 10-s long sequence of 35-ms exposures at 10 Hz. <b>B.</b> Fluctuations in the outputs of the same sources in a 12-h long sequence of 500-ms exposures at 5 minute intervals. Inset: detail at higher magnification. <b>C.</b> Drift and noise of measured light output from LED lamp with (black) and without (gray) optical feedback at short time scale (top) and long time scale (bottom). Please see text for comparison to a current-generation xenon arc lamp.