Laser-induced grating self-diffraction from a medium with induced absorption

There are a great variety of optical nonlinearities that can lead to the phenomenon of laser-induced gratings (LIG) in semiconductors. In the present contribution the dynamic behaviour of an induced absorber with intrinsic bistability is investigated under excitation in a LIG self-diffraction arrangement. Using CdS as a model substance, the comparison of our theoretical model with our experimental findings gives an insight into the nonlinear dynamics of the degenerate carrier system and also an estimation of the transport properties of the electron-hole plasma.     

ZnO: material, physics and applications.

ZnO is presently experiencing a research boom with more than 2000 ZnO-related publications in 2005. This phenomenon is triggered, for example, by hope to use ZnO as a material for blue/UV optoelectronics as an alternative to GaN, as a cheap, transparent, conducting oxide, as a material for electronic circuits that are transparent in the visible or for semiconductor spintronics. Currently, however, the main problem is to achieve high, reproducible and stable p-doping. Herein, we critically review aspects of the material growth, fundamental properties of ZnO and ZnO-based nanostructures and doping as well as present and future applications with emphasis on the electronic and optical properties including stimulated emission.     

Relaxation mechanism of the 1Δg state of liquid O2

Collisional deactivation of the first excited electronic ¹Δ_g(υ = 0) state of O₂ involves intersystem crossing to higher vibrational levels (υ < 5) of the electronic ground state ³Σ^?_g. It is followed by rapid vibrational-vibrational energy exchange which populates the first excited ³Σ^?_g(υ = 1) vibrational level. The suggested relaxation mechanism is supported by experimental results on the time dependence of the populations of the ¹Δ_g(υ = 0) and ³Σ^?_g(υ = 1) states in liquid natural O₂ and ¹⁸O₂.