The average power and efficiency of processes that exhibit low interaction cross section and low optical loss can often be enhanced by recirculating the laser pulse in the cavity. Inverse Compton scattering of the photon pulse on an electron bunch, harmonic generation, and spectroscopy represent examples of such processes. Methods for laser recirculation that enhance the interaction efficiency have been proposed in the past, based on resonant cavity coupling, intracavity amplification, or electro-optical switching. Those methods exhibit limitations such as interferometric alignment accuracies, complexity, and nonlinear phase accumulation. A novel scheme for energetic short laser pulse recirculation, termed recirculation injection by nonlinear gating (RING), is described. RING is based on intracavity nonlinear frequency conversion for optical switching, does not exhibit interferometric alignment constraints, and is scalable to extreme peak power. Initial demonstration of the RING technique is presented at a 1-mJ level, with cavity enhancement factors exceeding 25 in a simple unstable resonator cavity. Applications of the RING technique in biomedical and other applications are outlined.