Dielectric slot-coupled half-Maxwell fisheye lens as octave-bandwidth beam expander for terahertz-range applications
Abstract
We present a paradigm for integrated photonic devices based on broadband slab-confined collimated beams that are launched with half-Maxwell fisheye lenses. Although it is challenging to match to the low-index focus of the lens while maintaining adequate field confinement for a close approximation of a point source, integrated dielectric slot waveguides prove highly suitable, yielding collimators of 90% efficiency and bandwidth greater than one octave. Terahertz technology will benefit from such broadband slab-confined beams to replace free-space optics toward compact, mass-producible systems that do not require manual optical alignment. We present two prototype systems to demonstrate the versatility of this concept, namely, a diagonally set distributed Bragg reflector as a frequency-division diplexer for terahertz communications and an attenuated total reflection-based liquid sensor. Both are enabled by oblique in-slab reflections that are collected at a location other than the originating lens, which is not attainable using ordinary single-mode channel waveguides.
- Publication:
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APL Photonics
- Pub Date:
- September 2021
- DOI:
- 10.1063/5.0054251
- arXiv:
- arXiv:2101.11210
- Bibcode:
- 2021APLP....6i6104H
- Keywords:
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- Physics - Optics;
- Physics - Applied Physics
- E-Print:
- 10 pages, 6 figures