An apparatus for simultaneously imaging a subject and displaying computer generated image (“CGI”) light to the subject includes a display array and a photodetector array. The display array and the photodetector array are disposed on a same semiconductor die. The display array includes display pixels configured to selectively generate the CGI light to be sent along a forward optical path. The photodetector array is positioned to receive non-visible image light that is reflected by the subject and directed along a reverse optical path. The CGI light to be sent along the forward optical path travels in a substantially opposite direction as the non-visible image light directed along the reverse optical path.