The Interaction of Light with Materials

Raman scatterings are due to the interaction of light with material vibrations. Let q be the normal vibrational coordinate and let U q) be the potential energy associated with this mode. Because of the optical field displacement qy on q, the polarizability a(q) of the atom (or molecules comprising the nonlinear material) becomes... 

NLO effects arise from the interaction of light with loosely held electrons, typically, in the case of organic materials, those associated with conjugated Ji-systems. In the following section we examine the details of this interaction. 

AOTFs (101, 102) work on a different principal. This type of filter functions by the interaction of light with a traveling acoustic wave in an anisotropic medium. Both crystals and polymers have been used for the anisotropic medium. An acoustic transducer is bonded to one end of the material and an... 

The interaction of light with matter has fascinated people since ancient times. The color of an object is the result of this interaction. In modem terms, this interaction is described as spectroscopy. In this chapter, how the optical properties of a material are the result of its chemical composition and stmcture are examined. Several examples of technologically relevant applications are then presented of the manipulation of the optical properties to achieve a desired performance. 

In one sense, this is an easy topic. All of the interactions of light with matter can be described with Maxwell s equations (Griffiths, 1981). However, for the materials chemist faced with the problem of designing a glass lens that does not reflect visible light. Maxwell s equations, in their native state, do not appear to offer a straightforward solution. Fortunately, Maxwell s equations have been solved for most of the problems encountered in materials design. Here, one such case is examined. 

Imagine a material that is diamagnetic, transparent, and is an insulator a piece of glass When solving Maxwell s equations for the interaction of light with this system, several important and unexpected results are realized. First, a plane polarized light... 

The interaction of light with a molecule can be described by the influence of its eleetric field on the electron density. The eleetric field E acting on the molecule (or material) induces a distortion of the electron density, with (induced) dipole moment / ind (or polarization P on the maeroscopic level). For weak electric fields the magnitude of this induced moment (polarization) can be expected to be linear with the amplitude of the electric field. This linear proportionality suffiees to explain the linear optical properties, e.g., refraction and optical activity. Yet, when the electric... 

So far, in the description of the interaction of light with matter, we have assumed that the response of the material to an applied optical field was independent of its magnitude. This approximation is valid when the electric field amplitude is negligible compared with the internal electric fields in atoms and molecules. However, when lasers are used as light sources, the intensity of the optical field is usually strong and can drive the electronic response of a dielectric into a nonlinear regime. This nonlinear optical response is described by a field-dependent susceptibility that can be written as... 

Optical biosensors comprise a rather heterogeneous group of sensors in which the interaction of light with an immobilized biologically active material is sensed. They often contain a light source in addition to the signal transducer. 

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