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.

Keywords:

• near-field
• tapered waveguide
• field enhancement
• wavefront modulation

Acknowledgements

The authors thank Li Li for useful discussions.