A laser-radiation sensor includes a copper substrate on which is grown an oriented polycrystalline buffer layer surmounted by an oriented polycrystalline sensor-element of an anisotropic transverse thermoelectric material. An absorber layer, thermally connected to the sensor-element, is heated by laser-radiation to be measured and communicates the heat to the sensor-element, causing a thermal gradient across the sensor-element. Spaced-apart electrodes in electrical contact with the sensor-element sense a voltage corresponding to the thermal gradient as a measure of the incident laser-radiation power.