Note: I said "phononic", not "photonic".
https://en.wikipedia.org/wiki/Phonon
https://www.technologyreview.com/2012/08/13/184508/how-to-bu...
https://en.wikipedia.org/wiki/Phonon
https://www.technologyreview.com/2012/08/13/184508/how-to-bu...
Sound waves (phonons) are probably worse