Patrik Micek

Herein, we report the near-field emission characteristics of hexagonal GaP nanopyramids (HNPs) grown by metal–organic vapor phase epitaxy (MOVPE) and integrated onto the end facet of a single-mode optical fiber, measured with a home-built scanning near-field optical microscope (SNOM). Finite-element simulations predict a strongly localized optical field at the gold-seeded apex, confined to lateral dimensions of approximately 100 nm, while the measured near-field maps show a localized emission spot with a full width at half maximum of about 700 nm, limited by convolution with the scanning probe. The good qualitative agreement between simulation and experiment indicates that MOVPE-grown GaP HNPs are promising candidates for apertureless near-field probes.

Herein we investigate the character of the near‐field emission of a two‐ (2D) and novel three‐dimensional (3D) probe geometries fabricated using 3D direct laser writing lithography. Near‐field scans in x – y and y – z planes were measured both before and after the deposition of hyperbolic dispersion metamaterial (HMM) to further verify the directional propagation of the high wave‐vector components present in the vicinity of the structures. Additional computational and theoretical characterization forewent the actual experimental measurements, showing a promising performance, particularly for the 3D Fresnel zone plate (FZP). Overall, the experimental data documents a subwavelength resolution with a significant signal enhancement in the focal spot of the 3D FZP and highly subwavelength depth of focus.

Recent advances in nanotechnology enabled the effective fabrication of artificially engineered composites with customized physical properties called metamaterials. Such non-natural behavior gave rise to many physical phenomena such as negative refraction, deep subwavelength imaging or cloaking. This paper presents the theoretical characterization of enhanced nanowire metamaterial structure consisting of anisotropic semiconductor nanowires. By changing the semiconductors parameters such as doping results in effective tuning of the hyperbolic dispersion of the metamaterial, which is not possible with noble metals. At last, the effects of the nanowires diameter, spacing and structure symmetry on hyperbolic dispersion were analytically investigated.

Recent advances in Surface Plasmon Resonance (SPR) technologies have shown the possibility of transmission enhancement of localized modes propagating through sub-diffraction wide slits and apertures, resulting in the strong near-field focusing of metallic planar nanostructures. This work presents a new approach to the fabrication of high-resolution near-field optical probes using 3D lithography in combination with numerical finite difference time domain (FDTD) simulations. A narrow 500 nm depth of field focus area was observed both by numerical analysis and near field scanning optical microscopy (NSOM) measurements. Further research and optimization are planned in order to achieve subwavelength focal regions and increased signal intensities.