A laser power meter incorporating an absorber disc with a peripheral thermopile ring, either continuous or segmented, and an additional temperature detection element in the central portion, that enables measurement of beam size. This detection element can be a thermopile element, generally a ring of smaller diameter than the peripheral thermopile used, and located closer to the center of the absorber disc. With this arrangement the beam size can be measured, in addition to measurements of the power and the position of the beam. Alternatively, this centralized detection element can be a single thermocouple junction located at the center of the disc, which acts as the hot junction of a thermocouple pair. The second or cold junction is effectively located on the disc close to the peripheral thermopile. Alternatively, two temperature measuring elements can be used, one at the disc center and one at the periphery.