File:ActiveMirror.png

Historical picture of the first active mirror reported at

http://bookstore.spie.org/index.cfm?fuseaction=detailpaper&cachedsearch=1&productid=143686&producttype=pdf&CFID=4525539&CFTOKEN=12257465

K. Ueda, N.Uehara. Laser-diode-pumped solid state lasers for gravitational wave antenna. Proceedings of SPIE, vol.1837, 336-345 (1993).