Interference optical measurements

Fig. 4.21. Schematic representation of continuous craze and retarded crack growth in RCG as derived from interference optical measurements...

Adapted with permission of lOP Publishing Limited from Schinker, M.G. and Doell, W. Interference optical measurements of large deformations at the tip of a running crack in a glassy thermoplastic in lOP Conf. Series No.47, Chap 2, p.224, lOP, 1979. 

Although the determination of the stress in coatings is an important task, the sol-gel literature is very scarce. Sol-gel coatings for optical applications are often amorphous and have thicknesses between 40 and 1000 nm. In this case, the stress determination by XRD or Raman spectroscopy is quite difficult. The investigation of thick layers is easier, but it has to be taken into account that, for oxide layers, the stress depends on the total film thickness. Therefore, bending-substrate techniques, combined with interference-optical measurements of the substrate curvature, are superior to other techniques. 

The BioView sensor (DELTA Light Optics, Denmark) was developed especially for industrial applications. It is capable of completely automatic optical measurement for monitoring and control of different bioprocesses. The instrument is conceived to withstand harsh industrial environments (e.g., high temperature, moisture) and electromagnetic interference. For data transfer a single-fiber asynchronous modem is used, which allows a distance between the computer and spectrometer of up to several hundred meters. 

S. Mukamel I would like to make a comment regarding interference effects in quantum and classical nonlinear response functions [1, 2]. Nonlinear optical measurements may be interpreted by expanding the polarization P in powers of the incoming electric field E. To nth order we have... 

Let us illustrate the benefits of higher order on a concrete analytical example measurements of concentration of Mg2+ with an ISE and with an optical sensor. After linearization of the potentiometric signal, the two experiments can be displayed as a bilinear plot (Fig. 10.2). Contained in this plot is an unusual sample point S, which clearly falls out of the linear correlation because it lies outside the statistically acceptable 3a noise level. This outlier is an indication of the presence of an interferant. Its presence is clearly identified in this bilinear plot from combined ISE and optical measurement, although it would be undetected in a first-order sensor alone. 

Reference to atomic interference is of interest for other reasons, too. One can study the properties of elementary particles by observing and precisely measuring various fine effects in the bound states. From such measurements, in principle, one can obtain such details as the behaviour of interactions at short distances, which otherwise are manifested only at very high energies. Optical measurements are probably among the most precise. If one adopts this form of measurement it is natural to ask whether it is possible to consider some phenomena of atomic physics within spec-... 

Fig. 1.1. Crack and craze openings in PMMA as measured by interference optics (points) (Arrangement of molecules and deformation behavior of fibrils are schematically indicated)...

Fig. 4.23. Craze growth in plasticized PVC (6% DOP) during RCG characterized by relative craze length s/s versus relative cycle number N/N as measured by travelling microscope and by interference optics...

Figure 3.16. (a) Detail from Fig. 3.15 of the experimental microhardness Hexp in the crazed zone, (b) Craze opening (2d) vi length ( ) of the same craze shown in (a) measured by interference optics. (From Michler era/., 1999.)... 

The craze length derived from microhardness indentation measurements has been compared with the length measured by interference optics. An enlarged section of Fig. 3.15 is shown in Fig. 3.16(a). Figure 3.16(/ ) shows the contour of the same craze measured by optical interferometry. It is seen that the craze length derived... 

Bl. Babul, J., and Stellwagen, E., Measurement of protein concentration with interference optics. Anal Biochem. 28, 216-221 (1969). 

Several of the amorphous alloys made by vapour quenching were investigated by means of substrate-incident magneto-optical measurements. The substrate-incident Kerr effect (different from the film-incident Kerr effect. The substrate-incident Kerr effect, in the absence of interference, can be obtained from eq. (6) by substitution of z /2/ns and 81/2/ns for e1/2 and 81/2, respectively (ns is the refractive index of the substrate). For the red and the infrared region, where the dielectric constant of metals is much larger than unity, one obtains... 

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