Improving near-field throughput in a hollow metallic tapered waveguide via wavefront modulation

Abstract

Throughput enhancement through a 100 nm-aperture hollow tapered aluminum waveguide via wavefront modulation was investigated numerically. The propagating modes in the waveguide are controlled and efficiently transformed to the fundamental propagating mode with optical wavefront modulations via a centro-symmetrical 9-bit binary optical element. Combined with the adjustment effect of the focal length of the coupling lens, an optimal throughput enhancement of about 11 times is obtained.

Photonic nanojet assisted enhancement in transmission of light through hollow pyramid shaped near field probes

“…Simulations were carried out to estimate the optimal transmission that can be achieved through an NSOM probe, having a pyramidal-shaped tip with an aperture of approximately 100 nm, by insertion of silica microspheres of different sizes. In addition to the size of the microsphere, we also considered the effect of illumination with a focused Gaussian beam, which can also influence the length of the PNJ [23,24]. The results of these studies show that the length of the nanojet generated with a diverging beam (beam waist located before the microsphere) is longer compared to that with the converging beam.…”