Well, Apple is working with a company called Rockley Photonics, who claims that they've done it: https://rockleyphotonics.com/rockley-unveils-end-to-end-digital

Well, Apple is working with a company called Rockley Photonics, who claims that they've done it: https://rockleyphotonics.com/rockley-unveils-end-to-end-digital-health-monitoring-solution/ https://rockleyphotonics.com/rockley-unveils-end-to-end-digi...