upward

Photoinduced structural changes

Tanaka K, Saitoh A, Terakado N, Giant photo-expansion in chalcogenide glass, J Optoelectronics Adv Mater 8, 2058 (2006)

Films

Krecmer P, Moulin A M, Stevenson R J, Reyment T, Welland M E, Elliott S R, Reversible nanocontraction and dilation in a solid induced by polarized light, Science 277, 1799 (1997)

Yang C Y, Paesler M A, Sayers D E, Measurement of local structural configurations associated with reversible photostructural changes in arsenic trisulfide films, PRB 36, 9160 (1987)