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Created by sebastien.popoff on 08/09/2020
Controlling multimode laser modes using wavefront shaping inside the cavity
[X. Wei et al., Light Sci. Appl., 9 (2020)] Multimode cavity lasers, such as multimode fiber lasers, are attractive for the opportunity they offer to generate high energy pulsed lasers, provided that one can achieve spatiotemporal mode-locking. However, it can be complicated to control the laser properties as 1) spatiotemporal dispersion, nonlinearity, gain and loss can nonlinearly interact, and 2) dispersion and mode coupling in such a system are difficult to predict or control. In a typical wavefront shaping experiment, one modulates the output of a laser beam, which can come at the cost of a significant energy loss, and only allows to control the spatial profile of the beam. In this paper, the authors use a spatial light modulator, but inside the laser cavity to modulate its boundary conditions. Using a genetic algorithm, they are able to efficiently control the laser properties, namely the output power, the output mode profile, the optical spectrum, and mode-locking. |
