Low‐temperature,T<90 K, illumination transfers transparent, single crystals of AlSb doped with Se to a metastable state characterized by a high optical absorption approaching 200 cm−1. The enhanced absorption spectrum extends from 0.1 to 1.5 eV and consists of a double band structure with peaks at 0.2 and 0.5 eV. It is induced by photons with a threshold energy of about 1 eV. It is persistent, i.e., it shows no measurable decay after switching off the excitation. The low absorption state is thermally recovered at 100 K. The persistent absorption is a manifestation of a DX‐type bi‐stability of the Se donor. The 0.2 and 0.5 bands are, respectively, due to the photoionization of electrons from the metastable hydrogenic donor level toX1andX3conduction band minima. A large binding energy of the Se donor is essential for the observation of persistent absorption and a lack of any free‐electron related effects. ©1995 American Institute of Physics.