Light propagation in dielectric plasmonic crystals with different parameters and symmetries was investigated by plasmon tomography. We show that the photonic Fermi surfaces at the crystal's reciprocal lattice space can be observed directly from the Fourier plane images. Directional gaps were observed where the isofrequency wavevectors of the propagating surface plasmon mode intersect the first Brillouin zone of the plasmonic crystal structures. We determined that the angular magnitude of the directional gaps depends strongly on the crystal symmetry and the lattice period.

We present a general discussion about the fundamental physical principles involved in a novel class of optical superlenses that permit to realize in the far-field direct non-scanning images with subwavelength resolution. Described superlenses are based in the illumination of the object under observation with surface waves excited by fluorescence, the enhanced transmission of fluorescence via coupling with surface waves, and the occurrence of far-field coherence-related fluorescence diffraction phenomena. A Fourier optics description of the image formation based on illumination with surface waves is presented, and several recent experimental realizations of this technique are discussed. Our theoretical approach explains why images with subwavelength resolution can be formed directly in the microscope camera, without involving scanning or numerical post-processing. While resolution of the order of λ/7 has been demonstrated using the described approach, we anticipate that deeper optical subwavelength resolution should be expected.

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We discuss two important consequences of recent experiments using surface plasmon polariton ͑SPP͒ tomography in a quantum eraser arrangement. In these experiments surface-emission images were modified by manipulating the polarization state of the leakage radiation. We show that SPP tomography does have the potential to produce images that mirror with high fidelity the propagation and interference of SPP beams at the metal-air interface of a sample. We reveal the physical mechanism behind this capability of SPP tomography. In addition, we show how SPP tomography can be used to detect photons passing through the dark fringes of an interference pattern and why photons propagate in such a way that looks like a photon can propagate across a region where it is never observed.

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