Azzam and Bashara

A good review article on optical constants and their measurement is that by Bell (1967). Determination of optical constants from reflectance measurements is treated by Wendlandt and Hecht (1966) and from internal reflection spectroscopy by Harrick (1967). Ellipsometric techniques are discussed at length by Azzam and Bashara (1977). 

Quantitative treatments of partially polarized light can be found in the texts by Born and Wolf [2], and Azzam and Bashara [5]. In this monograph, the light will be assumed to be perfectly polarized. It should be noted, however, that in many experimental situations depolarization can readily occur and care must be taken to either account for it, or to minimize this possibility. The most common source of depolarization in optical rhe-ometry is multiple scattering by such systems as dense suspensions and liquid crystals. 

The connection between the Stokes and Jones vectors, given by equation (1.59) can be used to relate the sixteen-component Mueller matrix to the four-component Jones matrix. Combining equations (2.1), (2.2), and (1.59), we have, using a notation similar to that developed in Azzam and Bashara [5],... 

Another important point is that reflection ellipsometers normally yield ratios of the reflection coefficients, R and Rm. The equations for these coefficients are nonlinear, transcendental, algebraic equations that must be solved simultaneously for the desired unknowns in an experiment. Techniques to solve these equations are presented in the monograph by Azzam and Bashara [5]. 

The reflectivity at stratified planar structures becomes more complicated if thin film structures are present. Still methods are available to make a straightforward calculation of the reflectivity. For thin film structures, a matrix method has been developed that still gives an analytical solution for the calculated reflectance (Azzam and Bashara 1977 Jackson 1998). 

The theory and practice or ellipsometry has been comprehensively treated by Azzam and Bashara. A more practically oriented treatment can be found in two more recent books, which serve as a better starting point for the intending practitioner. The following brief synopsis can only serve to highlight the main points or the technique. 

Many different designs of ellipsometers have been suggested and a good overview is presented in Azzam and Bashara [3]. Here we discuss common roots of all arrangements and the underlying theory. 

This chapter summarizes the optical principles involved in ellipsometry and reviews some typical applications in electrochemical systems. Newly developing areas of application and recent developments in the experimental approach and instrumentation will also be dealt with. Some emphasis will be on modified techniques, including the combined reflectance-ellipsometry method. Ellipsometry is a broad field that includes various techniques and a wide range of applications. The chapter is mostly devoted to showing what can be done with ellipsometry for the purpose of investigating electrochemical interfaces. Readers are referred to other sources of information on specific subjects. A thorough treatment of polarized light and ellipsometry has been published by Azzam and Bashara. The technique as applied to electrochemistry has also been subject to various reviews " and symposia. 

Imperfections or nonidealities of the optical components in an ellipsometer can cause errors in A and il/. Quantitative analyses of errors have been made by Jerrard for inexactness of the quarter-wave plate, by Azzam and Bashara" for nonideal optical activity of the quarter-wave plate and surface roughness, and by Smith" for finite bandwidths of the monochromatic light source as well as the source polarization. Archer and Shank" and Yolken, Waxier, and Kruger considered the effect of multiple reflection within the compensator plate. It is reported that antireflection coatings on the surfaces of the compensator plate are beneficial. Aspnes" treated in a formal way the first-order effects from... 

The Stokes vector representation of light polarization has often been used for ellipsometry measurements. (Another representation is the Jones vector representation, of which details can be found in the book by Azzam and Bashara listed under Further reading). In the Stokes representation, the polarization state of a light beam is given by its four-element Stokes vector,... 

R.M. Azzam and N.M. Bashara, Ellipsometry and Polarized Light, New York North Holland, 1977. 

Azzam R M A and Bashara N M 1977 Eiiipsometry and Poiarized Light (Amsterdam North-Holland)... 

Azzam RMA, Bashara NM (1977) Ellipsometry and polarized light. North-Holland, Amsterdam... 

Azzam RMA and Bashara WM (Eds), "Ellipsometry and Polarised Light", North Holland, Amsterdam, 1977. 

Azzam RMA, Bashara NM (1977) Ellipsometry and Polarized Light. North-Holland, Amsterdam Babikov YuL, Tashkun SA, Tyuterev VG, Champion JP, Pierre G, Wenger C (1993) Atmospheric Spectroscopy Applications Workshop, Reims, France Speclrochimica Acta Elcctronica (to be published)... 

R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light, North-Holland, Amsterdam, 1987 D. S. Kliger, J. W. Lewis, and C. E. Randal, Polarized Light in Optics and Spectroscopy, Academic, New York, 1990 S. Huard, Polarization of Light, Wiley, New York, 1996 C. Brosseau, Fundamentals of Polarized Light, Wiley, New York, 1998. 

Azzam, R., and Bashara, N., "Ellipsometry and Polarized Light, North Holland Publishing co., New York, 1977. 

---