I think the author's theory about the photo molecular effect are right!

Basically they say that the photons cleave water molecules from the surface of the hydrogels.

At first i was not convinced but then i read the abstract of the journal article (its not on scihub yet) and it changed my mind, the news article skipped over a few points:

https://www.pnas.org/doi/10.1073/pnas.2312751120?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed