A laser device is disclosed, the laser device comprising: a pump light source (2; 22) comprising one or more lamps configured to emit light (20); and a slab crystal (1; 21) having a front face, a back face, and four sides such that said back face and said sides are configured to reflect a laser beam (16) internally within said crystal (1; 21), said crystal (1;21) being configured to absorb energy obtained from said emitted light (20), wherein the slab crystal (1; 21) is configured to receive an input laser beam (16; 17) in the front face of the crystal (1; 21), with the crystal (1; 21) configured such that the laser beam (16) is reflected within the crystal (1; 21) more than two times while being amplified by the crystal (1; 21) using said received light energy, and wherein the input laser beam (16; 17) is thereby converted by the crystal (1; 21) into an amplified laser beam (17') emitted from one of the faces of the crystal (1; 21). Also, a system comprising a plurality of laser devices is disclosed.