Abstract <p>We study the oscillation of three-micron lasers based on Er³⁺:YAG, Er³⁺:Cr³⁺: YSGG, and Ho³⁺:Yb³⁺:Cr³⁺:YSGG crystals under optical pumping by pulsed diode arrays with a total peak power of up to 15 kW at a wavelength of 970 nm and a pulse repetition rate of up to 50 Hz. In a diode-pumped Er³⁺:Cr³⁺:YSGG laser, the maximum output energy of more than 0.8 J was achieved for the first time in the free lasing regime. In the case of active g-switching, the peak power of the output laser pulses with a duration of 55 ns exceeded 1 MW with an energy stability (standard deviation) of less than 3%. Using the developed laser systems as sources for stable pulsed pumping of a Fe²⁺:ZnSe single-crystal laser with a short optical cavity, pulses with a duration of less than 2 ns at a wavelength in the vicinity of 4.3 μm were obtained.</p>