Two techniques for modifying the spectral irradiance from a pulsed long arc xenon lamp to make it more comparable with the attenuation minimum (460-495 nm bandwidth) of deep ocean water were successfully tested. One technique applied the concept of shaping the current pulse by limiting the maximum amplitude and pulse width and produced a 50% improvement in irradiance in the 460-495 nm bandwidth over the present output of the NRL LIBEC photographic strobe. The second technique resulted in an additional improvement over the pulse shaping technique. In this technique, a metal was added to the interior of the flash lamp envelope. The three metals investigated were selected based upon the physical properties of low melting temperature and their prominent spectral lines in the 460-495 nm bandwidth. The three were zinc, cadmium, and zinc-cadmium. Improvements in irradiance of 24%, 28%, and 29% for zinc, cadmium and zinc-cadmium respectively were observed.
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