On/off switching in picoseconds employs tiny graphene sheets becoming electromagnetic under UV

https://phys.org/news/2023-12-onoff-trillionths-optically-magnetic-fields.html

"tiny disks on a 2X2 mm surface, each with 1.2µm diameter consisting of 2 graphene layers influenced by circularly polarized THz UV plasmons to excite electrons... the circular motions induced 0.5 Tesla electromagnetism... plasmon frequency can be adjusted via graphene disk diameter... used to influence other nearby materials... in quantum dots that illuminate screens, light color can be adjusted... as for magnetocaloric materials, they change temperature depending on the magnetic field applied"