Turn photons into neutrons, add electrons (from photons) to make hydrogen, fuse one part of the hydrogen into oxygen, bring the other part of the hydrogen into a combustion chamber, bring the oxygen from the fusion into the combustion chamber, burn oxygen and hydrogen, cool the water vapor, and you've got water from photons.
You can't turn photons directly into anything but SPRK or other energy particles.
Photons turn into neutrons with INVS, add electrons from BIZS, they make HYGN, fuse that into OXYG, add more HYGN, burn it, cool the WTRV, and you have DSTW.
I know how lasers in tpt work; you corrected my comment on how you can't turn photons into anything but SPRK and other energy particles and my reply above clarifies that I meant you can't turn photons directly into anything but SPRK and other energy particles.