content_image/366252.jpg
<img src='content_image/366252.jpg'>

condition | R | 2 + | T | 2 = 1). We can thus with a good approximation write T = $_{i/}$√$_{2 and}$ R = 1 $_{/}$√$_{2.}$ 

To conclude, we presented a detailed experimental analysis of SPP interferometry. There- fore, we analyzed LRM images of a Mach-Zehnder interferometer relying on elliptical Bragg mirrors, and we analyzed quantitatively the reflection and transmission of SPP waves by the lossless beam splitter BS . This leads to the experimental relations T = $_{i/}$√$_{2 and}$ R = 1 $_{/}$√$_{2}$ between the SPP transmission and reflection coefficients T, R of BS . We observed fringes oscillations with unit visibility at the two exits of the interferometer as well as the opposition of phase between the two signals I$_{1}$ and I$_{2}$ when changing the length of the two interferom- eter arms by an amount ± δ , i. e. when changing the phase by the quantity Δ = 2 k$_{SPP}$δ . The conservation of energy is fulfilled since we have I$_{1}$ + I$_{2}$ ≃ const. whatever the phase difference Δ. All experimental observations are in good quantitative agreement with the analytical calculations. This forms a solid base for further investigations or applications of SPP interferometry. 

For financial support the Austrian Science Foundation and the European Union, under 

