Dependence of refractive index

Ball V and Ramsden J J 1998 Buffer dependence of refractive Index Increments of protein solutions Biopolymers 46 489-92... 

Electrooptic materials. The dependence of refractive index on the electric field or the lattice polarization is referred to as the electrooptic effect ... 

Very much more is known about the theory of concentration gradients at electrodes than has been mentioned in this brief account. Experimental methods for observing them have also been devised, based on the dependence of refractive index on concentration (the Schlieren method) by means of interferometry (O Brien, 1986). Nevertheless, the basic concept of an effective diffusion-layer thickness, treated here as varying in thickness with fi until the onset of natural convection and as constant with time after convection sets in (though decreasing in value with the degree of disturbance, Table 7.10), is a useful aid to the simple and approximate analysis of many transport-controlled electrodic situations. A few of the uses of the concept of 8 will now be outlined. 

In all cases, the initial measurement is of a refractive index which is correlated to the refractive indices of a series of standard solutions of known concentration, with °Brix being the most common standard set. Figures A1.4.1 and A 1.4.2 illustrate the dependence of refractive index on concentration for a range of solutions. 

The third-harmonic generation method has the advantage that it probes purely electronic nonlinearity. Therefore, orientational and thermal effects as well as other dynamic nonlinearities derived from excitations under resonance condition are eliminated (7). The THG method, however, does not provide any information on the time-response of optical nonlinearity. Another disadvantage of the method is that one has to consider resonances at oj, 2w and 3o> as opposed to degenerate four wave mixing discussed below which utilizes the intensity dependence of refractive index and where only resonances at a) and 2a) manifest. 

Fig. 9 Wavelength dependence of refractive index of a thin film of hb-P20. Data for a thin film of PS is shown for comparison...

FIGURE 7.2 Dependence of refractive index of Teflon AF on glass transition temperature. (Fromhttp //www2.dupont.com/Teflon industrial/en US/), DuPont, 2008. With permission.)... 

Figure 11.13 shows the dependence of refractive index in plasma polymer film on energy factor W FM)c FM)t. The refractive indices of all the plasma polymers showed an increasing dependence on the value of energy factor W FM)cl FM). ... 

Figure 11.13 Dependence of refractive index on energy factor W (FM)c/(FM)m for cascade arc torch polymerization.

Frequency dependence of refractive index Kramers-Kroning equation... 

The polymers were characterised by NMR and matrix assisted laser desorption/ ionisation-time of flight MS (MALDI-TOF MS) [92]. They have variable indices of refraction (from 1.45-1.52), Tg from 265-350 °C, and long-term thermal stability at 623 K. The dependence of refractive index on wavelength were also measured and the constants of copolymerisation reaction were determined [92]. End-group analysis has been a reliable asset in PFCB chemistry and in particular for copolymerisation studies [92]. 

Among the third-order effects, of particular interest is the light intensity dependence of refractive index of the medium. This light control by light phenomenon, being an all-optical effect, provides the fastest photonic mechanism available. Another important application of photonics is derived from the intensity dependence of optical transmittance of materials. This phenomenon is the principle of optical power limiting used for sensor, human eye or electronic circuitry protection. The above two applications are the examples of the intensity dependent complex third-order optical susceptibility of a photonic medium. 

Concentration Dependence of Refractive Indices. We have measured concentration dependence of refractive indices for some dyc/polymer systems at 633 nm with a He-Ne laser. Figure 3 shows the concentration dependence of refractive index of PMMA films containing NBDA or QCA(22). This figure shows a linear relationship between dye content and refractive indices. Refractive indices of NBDA/PMMA films are higher than those of QCA/PMMA films. This shows that the linear polarizability of NBDA is larger than that of QCA, because NBDA has two double bonds. 

Figure 3. Dye content dependence of refractive index of PMMA films containing NBDA (o) or QCA( ) at 633 nm.

Figure 5 shows concentration dependence of refractive index for DAAB/PMMA films(iO). Refractive indices were measured for unirradiated and irradiated samples. Unirradiated samples include the trans form alone. Photoirradiation was carried out by a Hg lamp with a filter of V-VIA (Toshiba). The conversion of trans-tocis form in the photochromic reaction was 0.70 as calculated by using the molar extinction coefficients of both isomers. Similar to the results of measurements for NBD derivatives, refractive indices are higher in the region of higher any dye content, and refractive indices of unirradiated samples are higher than those of irradiated samples at any contents. It reflects the decrease in polarizability caused by disappearance of the jt-jt transition band of the trans form. 

Figure 5. Dye content dependence of refractive index at 633 nm for PMMA films containing DAAB before irradiation (o) and after irradiation ( ).

The intensity-dependence of refractive index can also be used to generate a phase conjugate signal, in which the phase of a carrier wave is reversed to correct for any phase distortions. 

Variation of refractive index of the MNA solution in various solvents at 20 C as a function of concentration was obtained using an Abbe refractometer. Refractive indices available,as shown in Figure 5, range from 1.4 to 1.5 with the solvents used, from which one can easily match the refractive index of silica optical fibers. Temperature dependence of refractive index in MNA saturated solutions,measured at 15 C and 250C,is tabulated in Table 2. Fluctuation of refractive index,as a result of the temperature variation, turned out to be approximately 0.0004/ 0, so that It is essential to control the solution temperature to better than 0.1 in this experiment,in order for only electronic nonlinear refractive index change to be effective. 

The most common type of universal detector by far is the differential refractive index (DRI) detector. (Here, the word universal denotes the ability to respond to all chemical functionalities.) It senses differences in refractive index between a moving (sample containing) stream and a static reference of mobile phase using a split optical cell. It responds well (at a moderate concentration level) to most polymeric samples, provided that they are different in refractive index from the mobile phase in which they are dissolved. Despite the temperature independence of the SEC separation phenomenon, the DRI is highly temperature sensitive as a result of the strong temperature dependence of refractive index. 

Table ft.1-92 Wavelength dependence of refractive index n of indium compounds at T = 300 K... 

Figure 1 shows the refractive index of bulk silicon. The application of different effective medium theories leads to different results. Figure 2 shows the comparison of the dependency of refractive index on porosity, determined by different effective medium approaches. A value of 3.4 for the infrared bulk value has been taken for the solid pore wall phase. The refractive index of porous silicon is expected to be lower than that of silicon, as porous silicon is a two-phase composite, being a mixture of air and solid phase (Theiss and Hilbrich 1997). 

The simple method of the refractometric analysis has been described [63, 64]. Using this method, it is possible, to carry out a quantitative description of radial distribution of refractive index. It was shown, that the dependence of refractive index of GRIN-element on its radius and molar part of monomer-diffuser has symbatic character (Figure 4) [63, 64]. 

A.N. Bashkatov, E.A. Genina, V.I. Kochubey, and V.V. Tuchin, Estimation of Wavelength Dependence of Refractive Index of Collagen Fibers of Scleral Tissue, Proc. SPIE 4162, 2000, pp. 265-268. 

The first observation of natural optical anisotropy was made in 1669 by Bartolinius in calcite crystals, in which light travels at different velocities depending on the direction of propagation relative to the crystal structure. The electrooptic effect, electric-field-induced anisotropy, was first observed in glass in 1875 by J. Kerr. Kerr found a nonlinear dependence of refractive index on applied electric field. The term Kerr effect is used to describe the quadratic electrooptic effect observed in isotropic materials. The linear electrooptic effect was first observed in quartz crystals in 1883 by W. Rontgen and A. Kundt. Pockels broadened the analysis of this relationship in quartz and other crystals, which led to the term Pockels effect to describe linear behavior. In the 1960s several developments... 

Gourbilleau and R. Rizk, Size dependence of refractive index of Si nanodusters embedded in Si02,J. Appl. Phys., 98 (2005) 013523. 

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