IR detector and emitter for fNIRS with Mega 2560

Hi!

I'm new to Arduino and I'm starting to do a single-channel Functional Near-infrared Spectroscopy project with it. I need an IR emitter to have the ability to send lights with wavelengths of near 750 and near 850 nm. And I also need the IR detector to work in this range. Can anyone introduce the detector and emitter with such features?

Thanks.