Abstract: The present invention relates to a method and to a device for sheathing a solid-state laser medium comprising an active solid-state core material coated with a sheath. According to the method of the invention: a) the core material, made in the form of an elongate bar along a fibre axis, is at least partially introduced into a capillary tube; b) a laser beam is focused onto an annular focusing zone of the capillary tube until said tube around the core material melts in said focusing zone but without melting said core material; and c) when the molten capillary material adheres to the core material, said core material and/or said capillary tube are moved in a direction collinear with the axis of the core.