there are several r&d companies like rockley trying to bring contactless optical measurement to market, e.g. https://www.diamontech.de/home https://www.diamonte

there are several r&d companies like rockley trying to bring contactless optical measurement to market, e.g. https://www.diamontech.de/home https://www.diamontech.de/home Most are based on quantum cascade lasers. go science :-)