Fundaments of optical far-field subwavelength resolution based on illumination with surface waves

Abstract

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.

Fourier plane imaging microscopy

“…4(b)) is dark. A comparison of these experimental findings with similar results obtained using UTC 9,14 suggests that the rings observed in the experiments described here correspond to leakage radiation coupled to evanescent waves excited in the surface of the PCs by scattering of the perpendicular illumination. While the origin of these rings have yet to be completely determined, we can analyze the expected resolution increase from the rings associated with this unexpected condenser by calculating the resolution limit of a compound microscope with a condenser, given by the following expression: 7,9,12 …”

“…In the experiments described here, no bulky microscope condensers were used; however, we show that our unexpected experimental results can be explained using the image formation theory developed for microscopes based on the use of UTCs. 14 diffraction crystallography, where the periodic structure of a crystal is determined from the recorded diffraction pattern. 15 However, the use of an objective lens in FPIM allows for better control of the optical environment and light collection with large numerical aperture.…”

Toward Phase-Recovery Optical Nanoscopes

“…1a. The presence of rings in the FP images is a signature of the illumination produced by plasmonic UTCs [29,30,39]. There are also 4 arcs in the FP image shown in Fig.…”

Exploiting evanescent-wave amplification for subwavelength low-contrast particle detection

“…[2]. It was, in fact, later shown that a dielectric layer is capable of doing similar amplification [14][15][16] for both parallel (p) and perpendicular (s) polarization, essentially triggering Fabry-Perot-like resonances. The existence of evanescent-wave amplification also for s-polarized light rules out the interpretation of the super-resolution effects through mimicking negative refraction in metals, as suggested in Ref.…”