Interference plane parallel plate

Multiple reflections within the specimen can also reduce the accuracy of quantitative measurements (51,52). The intensity of light transmitted through a plane parallel plate, after the interference fringes have been eliminated, is given by (53) ... 

The probe beam is split by the plane-parallel plate Pll into two beams. One beam passes through that region of the absorbing sample that is saturated by the pump beam the other passes through an unsaturated region of the same sample cell. The two beams are recombined by a second plane-parallel plate P12. The two carefully aligned parallel plates form a Jamin interferometer [273], which can be adjusted by a piezoelement in such a way that without the saturating pump beam the two probe waves with intensities I and h interfere destructively. 

Consider as an example the interference of light at the reflection from thin films (or from a thin plane-parallel plate Figure 6.7). The direction of a beam falling on the film is shown in the figure by an arrow. Splitting of the wavetrains occurs in this case at partial reflection... 

A practical realization of the multiple beam-interference discussed in this section may use either a solid plane-parallel glass or fused quartz plate with two coated reflecting surfaces (Fabry-Perot etalon. Fig. 4.41a) or two separate plates, where one... 

In the literature, particular methods of measurement of these values are described in detail [24, 27], Among them, let us describe a modified variant of the method using a fme slice [30 - 32], According to this method, a plane-parallel glass plate with known value of kd with accuracy up to 10" (standard) is placed simultaneously with the sample studied in a cuvette filled with an immersion liquid. The standard and the sample are turned to each other by finely polished edges. The path of interference bands on the interferometer output is recorded, and the difference between the refractive index of a selected point of the sample and the standard is determined by displacement of these bands on the standard-immersion liquid and the sample-standard borders. Then the value of the refractive index at any point of the sample is determined [30]. 

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