The influences of amplified spontaneous emission, crystal temperature and round-trip loss on scaling of CW thin-disk laser

In this paper, a model is built to explore how the parameters (amplified spontaneous emission (ASE), temperature and round-trip loss) influence the output power in a thin-disk laser. It is found that optical efficiency of the disk laser is reduced with the increase of ASE, temperature or round-trip loss. The parameters are optimized to maximize the output power based on our model. We find that it is necessary to balance the need to lower the temperature with the need to control ASE during the optimization process. But the balance becomes more difficult to achieve with the increase of round-trip loss. We conclude that output power of more than 2.6 MW with a single disk can be achieved, but the necessary disk size (more than 0.5 m) is far beyond the actual technical limits. But it is possible to achieve output power of over a hundred kilowatts using a 10 cm disk in the near future.

► We proved that ASE, temperature and loss influence the power scaling limit of disk laser.
► The ASE intensity depends on the product of disk size and gain coefficient.
► The optimized parameters of disk are achieved by analytic calculation.
► Achieving a hundred kilowatts output using a 10 cm disk is possible theoretically.