Data Written in Light An optical card stores data the way a disc does — etched microscopically and read by laser — on a card that fits in a wallet. It is used where records must be secure, offline, and durable for decades.

A wallet-size card that stores data as microscopic marks read by laser — like a slice of optical disc. Capacity reaches megabytes, far beyond a magnetic stripe.

They had their peak in high-security government ID programs; many systems have since moved to smart chips. The technology remains relevant where permanent, offline, tamper-evident storage matters.

Written areas are permanent — data can be added to unused space but not invisibly altered, which is exactly why the format suited identity documents.