An optical refrigerator for cooling an infrared detector or sensor, that includes a laser radiation source, a cooling crystal for receiving laser radiation from the source and to be cooled, an element to be cooled, and a thermal link in heat exchange between the crystal and the element to be cooled, in order to transfer frigories from the crystal to the element to be cooled. The thermal link comprises two plates having respective first ends in heat exchange with two distinct surfaces of the crystal, respectively, the two plates having second ends in heat exchange with the element to be cooled.