Optical characterization

In this chapter we review some of the most important developments in recent years in connection with the use of optical teclmiques for the characterization of surfaces. We start with an overview of the different approaches available to tire use of IR spectroscopy. Next, we briefly introduce some new optical characterization methods that rely on the use of lasers, including nonlinear spectroscopies. The following section addresses the use of x-rays for diffraction studies aimed at structural detenninations. Lastly, passing reference is made to other optical teclmiques such as ellipsometry and NMR, and to spectroscopies that only partly depend on photons. 

As an example of a more speeifie applieation, Figure 2 illustrates a metallo-graph—a light microscope set up for the characterization of opaque samples. Figure 3 illustrates a research-grade microscope made specifically for materials science, i.e., for optically characterizing all transparent and translucent materials. 

For applied work, an optical characterization technique should be as simple, rapid, and informative as possible. Other valuable aspects are the ability to perform measurements in a contactless manner at (or even above) room temperature. Modulation Spectroscopy is one of the most usehil techniques for studying the optical proponents of the bulk (semiconductors or metals) and surface (semiconductors) of technologically important materials. It is relatively simple, inexpensive, compact, and easy to use. Although photoluminescence is the most widely used technique for characterizing bulk and thin-film semiconductors. Modulation Spectroscopy is gainii in popularity as new applications are found and the database is increased. There are about 100 laboratories (university, industry, and government) around the world that use Modulation Spectroscopy for semiconductor characterization. 

Collins, A., and Taylor, R., Optical Characterization of Poly crystalline ZnS Produced via Chemical Vapor Deposition, Proc. 11th. Conf. on CVD, (K. Spear and G. Cullen, eds.), pp. 626-633, Electrochem. Soc., Pennington, NJ 08534 (1990)... 

K. Vedam (guest editor). Physics of Thin Films. Advances in Research and Development, Optical Characterization of Real Surfaces and Films, Volume 19,... 

Experimental Methodologies for Linear and Nonlinear Optical Characterization. 116... 

Summarizing, the linear optical characterization not only reveals important properties of organic molecules but also provides a necessary background for the nonlinear optical characterization, which will be discussed in the next section. 

Proceedings The 5th International Workshop on Laser Beam and Optics Characterization Editors H. Laabs and H. Weber. Publisher Technische Universitat Berlin - Optical Institute (2000)... 

Ousi-Benomar, W. Xue, S. S. I. cssard, R. A. Singh, A. Wu, Z. L. Kuo, P. K. 1994. Structural and optical characterization of BaTi03 thin films prepared by metal-organic deposition from barium 2-ethylhexanoate and titanium dimethoxy dineodecanoate. J. Mat. Res. 9 970-979. 

Here n5 and nm are the refractive indices of the microsphere and ambient medium, respectively, and R is the microsphere radius. To determine An and t from this equation, it is sufficient to measure AA for two wavelength, ly1 and A. In Ref. 36, this was done for A[ = 760 nm and A[ = 1,310nm. As the result the authors optically characterized a hydrogel nanolayer with 110-nm thickness and an extremely small excess refractive index of 0.0012, which was formed in situ in an aqueous environment. 

H. Schlick, F. Stelzer, F. Meghdadi, and G. Leising, Synthesis and optical characterization of new highly luminescent poly(m,p-phenylene vinylene) derivatives, Synth. Met., 119 529-530, 2001. 

H. Liang, J. Yan, and J. Lu, Synthesis and optical characterization of a novel blue luminescent polymer regioregular poly(l-alkoxy-2,4 -m-phenylene vinylene), Synth. Met., 142 143-145, 2004. 

C. Cimico, Electro-Optical Characterization of Organic LEDs, Photonics Spectra, July 66-68, 2003. 

The waveguides were optically characterized at X = 632.8 nm. The effective mode indices were determined by the m-line technique, based on a standard two prism coupling set-up. The refractive index depth profiles of the fabricated waveguides were reconstructed by the means of the inverse WKB procedure . 

Towe, K.M. Moench,T.T. (1981) Electron-optical characterization of bacterial magnetite. Earth Planet. Sci. Letters 52 213-220... 

Kohki Mukai and Mitsuru Sugawara, Optical Characterization of Quantum Dots Kohki Mukai and Mitsuru Sugawara, The Photon Bottleneck Effect in Quantum Dots Hajime Shoji, Self-A.ssembled Quantum Dot Lasers Hiroshi Ishikawa, Applications of Quantum Dot to Optical Devices Mitsuru Sugawara, Kohki Mukai, Hiroshi Ishikawa, Koji Otsubo, and Yoshiaki Nakata, The Latest News... 

Drozdova O, Yakushi K, Yamamoto K, Ota A, Yamochi H, Saito G, Tashiro H, Tanner DB (2004) Optical characterization of 2kp bond-charge-density wave in quasi-one-dimensional 3/4-filled (ED0-TTF)2X (X = PFg and AsFg). Phys Rev B70 075107-1/8... 

Zhang L, Tu X, Welsher K et al (2009) Optical characterizations and electronic devices of nearly pure (10,5) single-walled carbon nanotubes. J Am Chem Soc 131 2454-2455... 

Seet KK (2006) Fabrication of 3D spiral struciu e photonic crystals by femtosecond laser and their optical characterization. PhD thesis. Research Institute for Electronic Science, Hokkaido University, Sapporo, Japan... 

The systematic synthesis of non amphiphilic l.c.-side chain polymers and detailed physico-chemical investigations are discussed. The phase behavior and structure ofnematic, cholesteric and smectic polymers are described. Their optical properties and the state of order of cholesteric and nematic polymers are analysed in comparison to conventional low molar mass liquid crystals. The phase transition into the glassy state and optical characterization of the anisotropic glasses having liquid crystalline structures are examined. 

One purpose of this tutorial paper on optical characterization is to provide a brief introduction for chemists to the concepts and methods involved in studies of the nonlinear optical properties of molecules and materials. The intent is to familiarize chemists with the range of commonly used techniques and their physical basis. An attempt is made to provide some background on macroscopic nonlinear optics, relating to what is actually measured, and the connection to molecular nonlinear optical properties. This paper is not intended to be a detailed or comprehensive review. The reader is referred to introductory (1, 2) and advanced (3-6) texts on nonlinear optics for more detailed or complete coverage of the subject. 

In this paper it has been attempted to provide an introductory overview of some of the various nonlinear optical characterization techniques that chemists are likely to encounter in studies of bulk materials and molecular structure-property relationships. It has also been attempted to provide a relatively more detailed coverage on one topic to provide some insight into the connection between the macroscopic quantities measured and the nonlinear polarization of molecules. It is hoped that chemists will find this tutorial useful in their efforts to conduct fruitful research on nonlinear optical materials. 

Dos Santos, D. S., Alvarez-Puebla, R. A., Oliveira, O. N., and Aroca, R. F. (2005). Controlling the size and shape of gold nanoparticles in fulvic acid colloidal solutions and their optical characterization using SERS. J. Mater. Chem. 15(29), 3045-3049. 

A new family of Pt(II) polyyne polymers functionalized with substituted 1,4-diethynylbenzene derivatives 8—14 were synthesized and optically characterized by absorption and PL studies.20 In regard to the emission properties, it is interesting to see that the relative intensity of triplet emission increases strongly with the electronegative fluorine content in such system. 

Wang, X., Masumoto, H., Someno, Y., Hirai, T., (1998), Optical characterization of Si02-Ti02 thin films with graded refractive index profiles , J Japan Inst. Met, 62(11), 1069-1074. 

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