Probing photonic Bloch wavefunctions with plasmon-coupled leakage radiation

Abstract

We demonstrate theoretically and experimentally the direct observation of photonic Bloch wavefunctions in dielectric loaded plasmonic crystals. The ultimate ability to observe the Bloch wavefunctions in the surface emission images depends not on the light diffraction through the holes but on the strength of the in-plane light scattering from the individual lattice features and the presence of the metal layer which allows the light propagating within the crystal to be imaged in the far-field. Experimental results are in excellent agreement with simulated surface emission and back focal plane images of plasmonic crystals.

Momentum-space spectroscopy for advanced analysis of dielectric-loaded surface plasmon polariton coupled and bent waveguides

“…It provides a diffraction-limited snapshot of the mode profile in the structure, and, by conoscopic imaging enables to extract the wave-vector distribution. Effective indices of the different modes and interactions developing in a given structure can thus be readily determined [3,[17][18][19].…”

Toward surface plasmon polariton quantum-state tomography

“…11 The photons used to excite SPPs in that experiment were emitted by a true source of temporally spaced photons based on the spontaneous parametric downconversion (SPDC) phenomena. 22,23 Working toward SPP quantumstate tomography, we explore the quantum limit of SPP tomography, [24][25][26][27][28][29][30] also called the leakage radiation microscopy, 19-21 using a combination of two well established and understood methods: the single SPP excitation method used in Ref. 11, and the method for detection of photons coupled to SPPs used in Ref.…”

“…29,30 Classical SPP tomography allows for the direct observation of SPP Bloch function 27,28 and equifrequency curve dispersion 25,26 in plasmonic crystals where the surface waves are excited in leaky modes. In SPP tomography, the photons used for imaging are the ones that leak to the sample substrate regardless of the measurement process.…”

“…Consequently, this technique allows for non-disturbing observation of the SPPs excited in the sample. [29][30][31][32] Using typical SPP tomography arrangements, one can simultaneously obtain surface emission (SE) and Fourier plane (FP) images, which are maps of the spatial 21,27 and momentum 21,25,26 distributions of the excited SPPs, respectively. Therefore, SPP tomography allows for the characterization of excited SPP modes in the sample.…”

“…Leaked photons carry detailed information about the excited SPP modes, which can then be extracted from the SE and FP images formed in the microscope. [25][26][27] The determination of the SPP quantum state requires the excitation of numerous single SPPs in the same quantum state. This can be achieved using a typical SPP tomography arrangement.…”