You don't have to use magnetism or electrical charge to store data. It can be done using light, or more rather, the reflection of it. Okay, if you want to be really specific, it's done using the interference of infrared and visible electromagnetic waves, but let's not worry too much about that!
Your smart speakers are a little vulnerable right now
Lookin' for a heartbeat...
Captain America really can wield Mjolnir
Careful! You'll put your eye out with that thing
Researchers have already transmitted a song via "quantum cascade laser frequency combs"