I've seen the scuba stuff with tritium.
I go the low tech route for when I do night dives. I go to the dollar store and buy a bunch of those glow in the dark cylume plastic halloween things.
Just before entering the water, I give everyone a different color, break the vial inside and activate them, and that way, I know who is who underwater and if a flashlight breaks down, we know where that person is.
You and me both. :-)
I don't do many night dives anymore. Not much to see. However, have you ever lit up coral with a UV light? Pretty cool.