1995 | OriginalPaper | Chapter
The Linear Optical Response
Authors : Rodolfo Del Sole, Anatolii Shkrebtii, Jiang Guo-Ping, Charles Patterson
Published in: Epioptics
Publisher: Springer Berlin Heidelberg
Included in: Professional Book Archive
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The linear optical response theory considered in this chapter relates to the experimental techniques of reflectance anisotropy spectroscopy (RAS) [1–6] and surface differential reflectance (SDR) [7–15]. These experimental techniques were outlined in Ch. 1, and are described in detail in Ch. 4. This chapter describes calculations of the RAS and SDR spectra from clean and adsorbate-covered Si, GaAs and GaP surfaces. The experiments aim to extract information about how the narrow selvedge region at a surface contributes to the reflected electromagnetic field in vacuum. Thus, the field amplitudes in this region at the surface are a very important ingredient in the calculation. What provides an interesting challenge for the theorist in this problem is that the region where the field amplitudes need to be known accurately is also the region where they are changing very rapidly (over ~1 nm) from their vacuum values to the bulk values. We recognise three ill-defined regions (in the sense that their edges are not sharp), which are important in determining the optical response of a surface: I the vacuum region; II the (narrow) selvedge region; HI the bulk. Since the advent of modern surface science, probably the first attempt to include these three regions was in the work of Mclntyre and Aspnes [16]. This has come to be known as the three-phase model (see Sect. 1.3).