Photorefractive Materials and Their Applications 2

In this second volume of the book series devoted to photorefractive effects we focus on the most recent developments in the field of photorefractive materials and we highlight the parameters which govern the photoinduced nonlinearity. The availability of materials having the required properties is of major importance for further development of this field, and there are many parameters which have to be considered in the figure of merit of a photorefractive material. As an example, it concerns in priority, the recording slope of the dynamic hologram and the saturation value of the index modulation which are specific characteristics of a given material. However, other features like spectral sensitivity range, dark storage time, material stability and power handling capabilities are also critical parameters to consider when using the crystal for advanced applications in laser photonics. There are a large diversity of potential materials which exhibit interesting photorefractive properties, like ferroelectric or non ferroelectric electro-optic crystals, semi insulating semiconductors or electro-optic polymers. If the basic mechanisms for space charge recording are well established, it is now required to have a very precise and extended knowledge of the physics of the charge transfer and related mechanisms which arises in doped materials. Also, we must know the material response for different conditions of hologram recording wavelength, laser intensity, continuous or pulsed regime. These research achievements on the physics of the photorefractive materials is of great importance in order to optimize or to tailor material properties. The main purpose of this second volume is to highlight the advances in material research but also including crystal growing conditions or material preparations and their impact on photorefractive performances. Following this objective, the reader will find in this book very detailed analysis on the material physics : investigations