🧫 Droplet Microfluidic Sorter: Fluorescence Threshold and ROC (2D top view)

2D top view of a droplet microfluidic sorter: a T-junction makes water droplets in oil, a fluorescence detector reads each one with noise, and an electric field steers the ones above a threshold into a collection lane. Change flows, geometry, voltage, threshold and noise and watch purity, recovery and the ROC curve. Same droplet and sorting model as the 3D page, with four in-page numerical checks.