Linear and nonlinear intersubband optical absorptions in an asymmetric rectangular quantum well İ. Karabulut, Ü. Atav, H. Şafak and M. Tomak Eur. Phys. J. B, 55 3 (2007) 283-288 Published online: 21 February 2007 DOI: 10.1140/epjb/e2007-00055-1