Laser Stand for Measuring the Radiation Resistance of Optical Elements at a Wavelength of 2.87 $$\boldsymbol{\mu}$$m

This paper reports on the development of a laser stand based on a Cr:Yb:Ho:YSGG laser ( $$\lambda=2.87$$ $$\mu$$ m) with a pulse energy of 15 mJ and a pulse duration of 40 ns, operating in Q-switched mode. The stand is designed for measuring the radiation resistance of optical elements used at the wavelength range of 3 $$\mu$$ m and for other experiments on the interaction of radiation with matter. The features of measuring the laser radiation caustics near the focal plane of a lens with $$f=50$$ mm using the scanning knife-edge method with different temporal structures of the radiation pulse are discussed. The energy density on the surface of the optical element under study with a laser spot diameter of $${\approx}$$ 160 $$\mu$$ m can be smoothly varied within the range of $$1{-}52$$ J cm $${}^{-2}$$