Metamaterial Tapered Waveguide on a Chip may boost Solar Cell efficiency


waveguide taper arrayIn breakthrough photonics research from University at Buffalo, a nanoscale microchip component called a “multilayered waveguide taper array” has been demonstrated that absorbs each frequency of light at different places vertically to catch a “rainbow” of wavelengths, or broadband light.

Unlike current chips, the waveguide contains specialized tapers, the thimble-shaped structures pictured here.

The work opens up new possibilities for more efficient photovoltaic cells, improved radar and stealth technology and new ways to recycle waste heat generated by machines into energy.

Each multilayered waveguide taper is comprised of ultrathin layers of metal, semiconductors and/or insulators. The tapers absorb light in metal dielectric layer pairs, dubbed hyperbolic metamaterial.

By adjusting the thickness of the layers and other geometric parameters, the tapers can be tuned to different frequencies including visible, near-infrared, mid-infrared, terahertz and microwaves.

On-chip Optical Communication

One relatively new field of sophisticated computing research called on-chip optical communication may benefit from this breakthrough.

In this field, there exists an occurrence called crosstalk. Crosstalk is when an optical signal transmitted on one waveguide channel creates an unwanted scattering or coupling effect on another waveguide channel. The multilayered waveguide taper structure array potentially could prevent this.

It may also advance the state of the art in thin-film photovoltaic cells, promising because less expensive and more flexible that traditional solar cells. Their drawback, is that they don’t absorb as much light as traditional cells.

Since the multilayered waveguide taper structure array can efficiently absorb the visible spectrum, as well as the infrared spectrum, it could potentially boost the amount of energy that thin-film solar cells generate.

Industrial and Consumer Applications

The multilayered waveguide taper array might also help recycle waste heat generated by power plants and other industrial processes, in addition to electronic devices such as smart phones, televisions, and laptop computers.

It could potentially even be used as a stealth cloaking material for aircraft, marine ships and other vehicles to avoid radar, sonar, infrared and other forms of detection.

References:

Dengxin Ji, Haomin Song, Xie Zeng, Haifeng Hu, Kai Liu, Nan Zhang & Qiaoqiang Gan Broadband absorption engineering of hyperbolic metafilm patterns Scientific Reports 4, Article number:4498 doi:10.1038/srep04498

Waste heat recovering: Technology and Opportunities in, U. S. Industry. BCS, Incorporated (2008) (Date of access: 12/01/2010): https://www1.eere.energy.gov/manufacturing/intensiveprocesses/pdfs/waste_heat_recovery.pdf

Linic, S., Christopher, P. & Ingram, D. B. Plasmonic-metal nanostructures for efficient conversion of solar to chemical energy. Nature Mater. 10, 911–921 (2011)

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