Superconducting Nanowire Single-Photon Detector (2D)

A meandering superconducting nanowire is drawn schematically from above, biased just below its critical current. Fire single photons at it and watch each absorption nucleate a resistive hotspot that snaps across the wire's width, forces the bias current to detour, and produces a sharp voltage pulse on the oscilloscope trace before the wire cools back to zero resistance. Slide the bias current below its optimal window and photons stop registering; push it above the window and the wire starts firing — or latching — on its own, with no photon required. This is the 2D companion to the 3D SNSPD simulator: identical bias-window physics, rendered as a flat top-down schematic instead of an orbiting 3D chip.