A static resonator for industrial Nd:YAG lasers was designed. Regardless of the thermal lensing effect acting on the YAG rod, this resonator keeps the multimode laser beam divergence θ quite constant (Δθ/θ<5%) under operational pumping power. At the same time, it maintains either the beam radius w or w×θ within a range permitting constant coupling of the beam into a fiber. The far field distribution of the beam could either be flat-top or quasi-Gaussian. θ, w as well as beam profile are determin
