Besides the introduced unimorph setup, other DM setups exist.3,5 These days, electrostatically activated mirrors6,7 and electromagnetically activated mirrors8,9 are especially popular. The advantages of these mirrors include their great actuating capabilities, the facility of using a large number of actuators, and their manufacturing based on batch-fabrication; however, their thin deformed mirror membranes make the application in high-power laser systems difficult owing to the challenge of low stress application of high-power coatings and low heat dissipation within the membrane. Nevertheless, occasional examples of intracavity laser application have been given.10 In contrast, piezoelectrically activated DMs are widespread in the field of laser beam shaping.11–13 From their inception, unimorph (and bimorph) DMs have been applied to the compensation for thermal lensing,14,15 and this is still the case. These days, unimorph and bimorph DMs with customized mirror coatings, mirror substrates, and actuating designs are commercially available from different companies, e.g., Cilas, TURN, and Active Optics NightN, but their thermomechanical design is not very sophisticated; in the case of homogeneous loading, by default, the differences in thermal expansion between substrate and piezoelectric layers are minimized, thereby minimizing the bimetal effect of the active mirror and leading to an athermal mirror design. Practical realizations of athermal designs result in glued lead zirconate titanate (PZT) disks on BK10 glass or Pyrex substrates.16,17 Another practical realization exclusively uses piezoelectric disks glued together and polished to optical quality.18 An alternative athermal setup is the application of a piezoelectric layer on thermally adapted metal. Suitable metals (with a coefficient of thermal expansion (CTE) around ) include titanium, AlSi70, W80Cu20, Mo80Cu20, and W85Cu15 with corresponding thermal conductivities of 7.6, 120, 248, 165, and , respectively. These metal-based substrates are not popularly used, as their manufacturing and finishing leads to increased labor costs compared with those of glass substrates. The presented athermal approaches neglect the use of the metallization layer of the piezoelectric elements as well as the joining layer because they are much thinner than piezoelectric elements and mirror substrates in relative terms. Moreover, manufacture-imposed variations of the CTE of the piezoelectric layer, which generates a bimetal effect with the substrate, are widespread and tremendously challenging, and thus the athermal design is no longer valid.