09/04/2026
⌛Physics Friday⏳
Do you know how scientists catch a single particle of light?⚛️
Superconducting Nanowire Single-Photon Detectors (SNSPDs) are ultra-sensitive light sensors that power quantum computing and deep-space laser communications! Detecting single photons requires extreme cold, relying on superconducting materials that conduct electricity with zero resistance.
Scientists start by cooling an ultra-thin wire down to near absolute zero, allowing an electric current to pass through effortlessly. When a single photon hits the wire, its energy creates a localized hotspot. This small burst of heat momentarily breaks the superconducting state, creating a sudden roadblock of electrical resistance. The current surges around this spot, producing a voltage pulse that signals a photon has landed. Within nanoseconds, the wire cools back down, resetting the sensor to catch the next particle of light!