A rigorous analytical treatment of nonradiative deexcitation and thermal‐conduction transient evolution in solid‐state laser media, resulting from intense optical pumping with rectangular pulses from a time‐gated laser source, is presented. This situation arises in rate‐window photothermal detection from laser rods with bulk and surface absorptions, the latter being due to polishing during the manufacturing of the rod. Numerical simulations of the theory show that the surface nonradiative (optical‐to‐thermal) energy conversion term is likely to dominate even at absorptances on the order of 1%–2%. Therefore, polishing optimization appears to be necessary in order to minimize laser losses at the surfaces when laser rods are active in a resonator cavity. The present theory also provides physical insights into the very different nature of the bulk‐ and surface‐originating heat‐conduction transients, as well as on the profile of the superposition photothermal wave form and its dependence on the optical, thermal, and metastable‐state relaxation parameters. As a prelude for input to the photothermal theory, a treatment of the excited‐state dynamics of a typical laser manifold pumped by an intense laser beam, away from or near saturation, is developed, and the luminescence and photothermal energy source profiles are calculated analytically. ©1996 American Institute of Physics.