An optical pumping structure for lasers includes: an active medium in the form of a cylindrical rod with a circular cross-section, said rod being inserted at its ends into two rings made of a thermally conductive material; at least three stacks of pumping diode strips arranged in the form of a star around the rod; and a support temperature-regulated by a Peltier-effect module. The rings are in contact with the support, and a stack of diodes, called bottom stack, being situated between the rod and the support, and the structure comprises, for each other stack, a thermal conduction block forming a support for said stack, these blocks being mounted on the cooled support and not being in contact with one another or with the rings.