Tech-led.com 
Functional near-infrared spectroscopy (fNIRS) measures brain activity by shining near-infrared light through the scalp and skull and detecting how much is absorbed by oxygenated and deoxygenated hemoglobin in the cortex. Building an fNIRS device requires at least two NIR wavelengths that straddle the ~810 nm hemoglobin isosbestic point — most commonly a pairing around 760…
