Maker fringes

Figure 1. Schematic illustration of sample geometries and THG interference fringing patterns, a). Wedge sample geometry, x is the cell displacement direction, b). Wedge THG interference fringes as a function of x. c). Slab sample geometry, 8 is the angle of incidence, d). THG interference fringes as a function of 8 (Maker Fringes).

Tg = 125-140°C, and was stable in a N2 atmosphere to 220°C. The 13C NMR spectrum revealed the presence of 7t-interaction between those chromophoric groups that are in isotactic relationship to each other ( 30-35% of total). The orientation of the chromophores in a PPNA sample (Tg = 125°C) was achieved in a thin film by the corona poling technique at temperatures above Tg. The subsequent freezing process resulted in a polymeric film that exhibited an initial high second-order nonlinear coefficient, d33=31 pm/V, as measured by Maker-fringe technique with 1.06 im fundamental. 

Figure 6. Plots of Maker-fringe data for a poled PPNA film of 1.2pm thickness at room temperature (P=p polarization, S=s polarization). (Reproduced with permission from Ref. 12. Copyright 1989 American Institute of Physics.)...

There are three non-vanishing SHG coefficients, d33, d31 and dii, for R3c. By means of the Maker fringe technique and the phase-matching method, Chen et al. [28] determined the values of these SHG coefficients shown in table 3 The very large anisotropy of the SHG effect is just as expected, with d33/dii 0 001. Li... 

X(3) values for a number of amorphous polysilanes as measured by the Maker fringe technique are reported in Table I. These values are quite large for a sigma-bonded system as predicted by the highly polarizable nature of the polymer backbone and the intense oa electronic transition in the ultraviolet. In some cases, the numbers are as large as those reported for a number of pi conjugated polymers... 

See Kajzar, F. Messier, J. In Nonlinear Optical Properties of Organic Molecules and Crystals. Chemla, D. S., Zyss, J., Eds. Academic Press, Inc. New York, 1987, Vol. 2, Chap. III-2 for an excellent description of the experimental details of the Maker fringe technique. 

For evaluation of the SHG activity, the Maker Fringe method was used [70]. AY-cut quartz plate (d = 0.81 X 10 °esu) was employed as the reference [71]. A mode-locked Q-switchedNd YAG laser was used as the fundamental beam source (1064 nm wavelength). 

From the Maker fringe technique, we obtained a d3j value of 50 pm V (contains resonant effect due to some absorption in SHG range) for PI-SOT. Since the relationship d33 = 3d3i holds in the polymer systems, the d33 value is supposed to be about 150 pm From the calculation with the approximate two-level model,... 

The Maker fringe method is one of the most used methods for determining the second-order nonlinear susceptibility x /t of a crystal [27]. It is a relative method and is only useful when the second-harmonic signal is compared with the signal from a crystal with known values. The experiment is designed as follows. 

For non-phased THG, the Maker fringe or wedge-shaped fringe method is used to determine the coherence length of the material, I,.. The coherence length is defined as ... 

Jerphagnon, J., Kurtz, S.K. Maker fringes a detailed comparison of theory and experiment for isotropic and uniaxial crystals, J. Appl. Phys. 41, 1667-1681 (1970)... 

Wedge method changes sample pass length by parallel displacement of wedgelike sample Maker fringe method changes sample pass length by the rotation of sample... 

The third-order NLO properties of some Ru species based on benzonitriles, including 103, 104, 106, and 108 (Figure 10) have been investigated in PMMA matrices using the Maker fringe THG technique 106 exhibited the highest value of 7(2280 x 10 esu, presumably resonantly enhanced, with a value for the film of 0.76x 10 esu). ... 

The third harmonic generation (TGH) measurement was performed using the Maker fringe technique at 1.907 fim. 

FIGURE 1 Maker Fringe Patterns from a parallel-slab cell (L = 375 pm) for an isotropic solution of PBT (cp = 0.021), with parallel polars for two incident wavelengths (a) 1542 nm and (b) 1907 nm. 

FIGURE 3 Maker Fringe Patterns for a nematic solution of PBT (9=0.055),... 

FIOIIBE. 4 Maker Fringe Patterns for a nematic solution of PBT (cp=0.055), with crossed polars and the incident polarization parallel to the director arrangement (a) H-v-V and (b) V-h-H. 

There are several techniques, both absolute and relative, which can be used to evaluate xfk components of a material [3]. However, in the case of polymeric materials the most useful method is Maker fringe method [6-8]. The general form of the second-order polarization created in a sample by the incoming fundamental beam can be approximated as [3]... 

In the Maker fringe method the sample is rotated in a plane perpendicular to the plane of the probing laser beam (Fig. 49.2), giving rise to a fringe pattern. The magnitude of the second-order polarization created in the sample depends on a number of parameters as shown in Eq. (49.9), where is... 

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