British researchers have created a new material that could allow for the creation of all-optical computers — computers that are orders of magnitude faster and power efficient than today’s hot, sweaty electronic beasts. This isn’t some crazy, hard-to-fabricate material like graphene, either — we’re talking about a special breed of chalcogenide glass.
You’d be forgiven for not knowing what a chalcogenide glass is, but trust me, you’ve all seen one — and probably made extensive use of them, too. Chalcogenide glasses are a family of (rather oddly behaved) materials that can readily change state between glassy and crystalline, which also changes their optical and and electrical properties. The recording layer of every rewritable CD and DVD consists of a chalcogenide glass (usually germanium-antimony-tellurium, GST) that changes state between glass and crystal when it’s struck by powerful laser, or can have its state read by a weaker laser, and can thus be used to store and retrieve binary data. Chalcogenide glasses are also used in modern, super-fast phase-change memory (pictured above), where a small heating element is used instead of a laser to change the state of a memory cell.
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