A memory device. The memory device includes a substrate and an array of nanocrystals formed proximate to the substrate. The array of nanocrystals is electrically insulated to hold charge carriers therein. A presence of charge carriers within the array of nanocrystals represents a first logic state of the memory device. An absence of the charge carriers within the array of nanocrystals represents a second logic state of the memory device. The presence and the absence of the charge carriers is determinable via directing a beam of photons onto the array of nanocrystals and sensing an optical response.