Mitigation of thermal blooming by rotating laser beams in the atmosphere

A novel method, to the best of our knowledge, for mitigating thermal blooming by using the rotating beam when propagating in the atmosphere is proposed. The rotating beam, generated by coherent superposition of two vortex beams with opposite topological charges and frequency shift, can directly modulate the heat source in time and then mitigate the thermal blooming in the atmosphere. The theoretical model of the rotating beam propagating in the atmosphere has been established, and the thermal blooming effects of the rotating beam and the conventional nonrotating beam through the atmosphere have been analyzed and compared. Results indicate that, compared to the nonrotating beam propagating in the atmosphere, the rotating beam is less affected by the thermal blooming and exhibits outstanding performance in mitigating the thermal blooming effect, resulting in smaller beam expansion, less shift of the beam centroid position, and better beam quality than those of the nonrotating beam.