<title>Unstable resonator power control without beam quality degradation</title>

High-Power Optics

“…According to the results of modelling intracavity optical systems [78][79][80][81][82][83][84][85][86], the use of adaptive POEs allows one to obtain the diffraction angular divergence of radiation fluxes when use is made of unstable resonators in high-power carbon dioxide laser systems. Adaptive POEs were essentially a new type of devices ensuring the local control of phase characteristics of coherent radiation fluxes.…”

“…In this part of the review we present the results of the studies on the creation of phase correctors of the beam path for laser systems based on POEs being cooled [79][80][81][82][83][84][85][86]. The shape of the reflecting surface is controlled in this case by the deformation of the porous structure of the heat exchanger.…”

“…This method is simple to implement and is widely used when creating precise adaptive POEs for highpower lasers and astronomical telescopes. At present, adaptive POEs of mirror type were created with an aperture diameter of one meter and the number of control channels (i.e., the number of actuators) up to several hundreds [75][76][77][78][79][80][81][82][83][84][85]. The study of adaptive POEs showed the versatility and high efficiency of this method for obtaining aberration-free fluxes of coherent radiation.…”

“…81 In this chapter, we consider the possibility of using linear iterative synthesis algorithm of the shape of a flexible adaptive POE under conditions of nonlinearity of hysteretic electromechanical properties of the individual actuators and their connection through a flexible substrate. We present the results of the experimental realization of the iterative algorithm and demonstrate its fast convergence.…”