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Compact, broadband meta-surface spectrometer

Meta-surfaces, planar arrays of subwavelength-spaced optical elements that modulate incident light, are poised to revolutionize the field of optics. Traditional optical elements are produced by labor-intensive glass molding techniques, and often require multiple components to function effectively for light of different wavelengths and correct for aberrations. Meta-surfaces can be fabricated by scalable manufacturing processes employed by the semiconductor industry and can match or surpass the capabilities of traditional lenses in a compact format.

The following inventions from Federico Capasso’s research group pertain to Meta-surface-based spectrometers. Spectrometers are useful in a range of applications, from monitoring environmental pollutants to detecting specific antibodies in diagnostics. Additionally, the ability to distinguish between chiral isomers is useful in the pharmaceutical and agrochemical manufacturing industries.

 

Broadband Multifunctional Efficient Meta-Gratings based on Dielectric Waveguide Phase Shifters (5938)

Meta-surfaces with dielectric ridge waveguides (DRWs) act as phase shift elements for incident light. By engineering the dispersive response of DRWs, high resolving power meta-gratings were realized with broadband (1.2-1.7 µm) capabilities, improving on traditional blazed diffraction gratings which are limited to operation at single wavelengths.

 

Super-Dispersive Off-Axis Meta-Lenses for High Resolution Compact Spectroscopy (6318)

A compact spectroscope composed of off-axis meta-lenses that can achieve focusing at very large angles (up to 80°), resulting in super-dispersive characteristics to resolve incident light of different wavelengths in the mid-infrared spectrum. By combining multiple meta-lenses designed to operate at different wavelengths onto a single substrate, spectral resolution is preserved across wide range (90% efficiency between 1.1-1.6 µm).

 

Ultra-compact, Aberration Corrected, Visible Chiral Spectrometer with Meta-Lenses (6599)

An ultra-compact chiral spectrometer capable of operating across the visible wavelength range and resolving chirality of incident light. Typically, broadband operation and chiral sensitivity require multiple lenses, linear polarizers and waveplate/retarder components, which are bulky and expensive. Improvements in nanofabrication, metalens design, and the combination of multiple lenses onto a single planar substrate allow for compact design and enhanced functionality. This spectrometer is compatible with a common CMOS detector and is highly scalable in terms of fabrication.

 

(L) SEM image of an off-axis meta-lens  (R) Photograph of a meta-spectrometer (meta-lenses and camera)

 

This work was published in Nano Letters and APL Photonics

Intellectual Property Status: Patent(s) Pending

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