Photonic lattice

From Memory Alpha, the free Star Trek reference

The photonic lattice is an energy structure encountered by the USS Voyager near a protostar in 2371. It appeared to shelter photonic lifeforms from the star, as well as the biological patterns of Harry Kim, Chakotay, and Tuvok after they were taken from the holodeck by "Grendel".

The lattice disappeared after a photonic lifeform trapped aboard Voyager was returned, in exchange for the three crewmen. Captain Kathryn Janeway speculated that it could have been something like a spacecraft for the aliens. (VOY: "Heroes and Demons")