A method for changing reflectance or resistance of a region in an optoelectronic memory device. Changing the reflectance of the region includes sending an electric current through the region to cause a reflectance change in the region. Changing the resistance of the region includes: projecting a laser beam at a first beam intensity on the region, resulting in the region changing from a first to a second different resistance value; electrically reading the second resistance value during which an optical signal carried by the laser beam has a first digital value; after electrically reading the second resistance value, the laser beam is projected at a second beam intensity on the region resulting in the region changing from the second to the first resistance value; and electrically reading the first resistance value of the region while the laser beam is being projected on the region at the second beam intensity.