Pulse 2.77-$\mu$m Cr$^{2+}$:CdSe laser with an output energy of 1.2 J

Due to the high value of the thermo-optical coefficient of the CdSe crystal, the energy characteristics of Cr$^{2+}$:CdSe lasers are limited to the development of a thermal lens. To reduce the effect of the thermal lens, a large-volume crystal was grown, which made it possible to increase the diameter to $\sim$5 mm and the length of the excitation region to $\sim$9 mm. As a result, the linear growth mode of the output energy of the Cr$^{2+}$:CdSe laser to a record value of 1.2 J with a differential laser efficiency of 51% in terms of absorbed pump energy was implemented.