  We report the experimental observation of surface plasmon polariton (SPP)
interference fringes with near-unity visibility and half-wavelength periodicity
obtained in back reflection on a Bragg mirror. The presented method based on
leakage radiation microscopy (LRM) represents an alternative solution to
optical near-field analysis and opens new ways for the quantitative analysis of
SPP fringes. With LRM we investigate various SPP interference patterns and
analyze the high reflectivity of Bragg mirror in comparison with theoretical
models.
