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Let There Be Light: Germans Switch on 'Largest Artificial Sun' (theguardian.com)
German scientists are switching on "the world's largest artificial sun" in the hope that intense light sources can be used to generate climate-friendly fuel. From a report: The Synlight experiment in Julich, about 19 miles west of Cologne, consists 149 souped-up film projector spotlights and produces light about 10,000 times the intensity of natural sunlight on Earth. When all the lamps are swivelled to concentrate light on a single spot, the instrument can generate temperatures of around 3,500C -- around two to three times the temperature of a blast furnace. "If you went in the room when it was switched on, you'd burn directly," said Prof Bernard Hoffschmidt, a research director at the German Aerospace Center, where the experiment is housed in a protective radiation chamber. The aim of the experiment is to come up with the optimal setup for concentrating natural sunlight to power a reaction to produce hydrogen fuel.
Another inane comment from the peanut gallery. While there is Hydrogen on the surface of the moon are you mistaking this with Helium-3? Otherwise your question makes no sense as if you want to refine hydrogen today the cheapest way to do it has nothing to do with space.
optimal setup for concentrating natural sunlight
But it's not. Sunlight is for all intents and purposes collimated due to the extreme distance of its source. While these lamps can be "swivelled (sp?) to concentrate light on a single spot", that will tell you little about the setup applicable for use with sunlight.
Have you heard about mirrors? And mirrors on swivels?
See also Solar power towers
xkcd explains it well: https://what-if.xkcd.com/145/
To sum it up, quoting from that link: Lenses and mirrors work for free; they don't take any energy to operate. If you could use lenses and mirrors to make heat flow from the Sun to a spot on the ground that's hotter than the Sun, you'd be making heat flow from a colder place to a hotter place without expending energy. The second law of thermodynamics says you can't do that. If you could, you could make a perpetual motion machine.