Sounds very interesting. Just started looking at the paper, which seems very complex to me "An alternative approach utilizes light absorption via localized surface plasmon resonances (LSPRs) of noble metal nanoparticles (NPs)".

I came across https://www.nano-resonance.com/ which appears to be the promotional page for the technique, it has a nice diagram which appears to show how the size of the silicon nanoparticle enhances certain wavelengths of light.

Very cool how they can use an inkjet printer for their approach.

Also see https://en.wikipedia.org/wiki/Lippmann_plate for a photographic process that creates colours using diffraction patterns.

https://www.youtube.com/watch?v=-DyrBDsKA5s is a fun video on lippmann plates.