title: Three-photon-induced four-photon absorption and nonlinear refraction in ZnO quantum dots.
abstract: Three-photon-induced four-photon absorption via excited-state absorption and self-defocusing nonlinear refraction are reported for the first time, to our knowledge, in ZnO quantum dots with average sizes of 2.0+/-0.1 nm with 1064 nm radiation from a Q-switched Nd:YAG laser at a peak intensity of 2.5 GW/cm(2). By employing the three-level two-step model, the experimental results can be explained quite satisfactorily.
authors: 1Department of Physics, National Institute of Technology, Durgapur 713209, India.
authors: M
authors: M
authors: Chattopadhyay
authors: P
authors: P
authors: Kumbhakar
authors: C S
authors: CS
authors: Tiwary
authors: A K
authors: AK
authors: Mitra
authors: U
authors: U
authors: Chatterjee
authors: T
authors: T
authors: Kobayashi