Subwavelength-thick Lenses with High Numerical Apertures and Large Efficiency Based on High Contrast Transmitarrays
Abstract
Flat optical devices thinner than a wavelength promise to replace conventional free-space components for wavefront and polarization control. Transmissive flat lenses are particularly interesting for applications in imaging and on-chip optoelectronic integration. Several designs based on plasmonic metasurfaces, high-contrast transmitarrays and gratings have been recently implemented but have not provided a performance comparable to conventional curved lenses. Here we report polarization-insensitive, micron-thick, high-contrast transmitarray micro-lenses with focal spots as small as 0.57 λ. The measured focusing efficiency is up to 82%. A rigorous method for ultrathin lens design, and the trade-off between high efficiency and small spot size (or large numerical aperture) are discussed. The micro-lenses, composed of silicon nano-posts on glass, are fabricated in one lithographic step that could be performed with high-throughput photo or nanoimprint lithography, thus enabling widespread adoption.
Additional Information
© 2015 Macmillan Publishers Limited. Received 17 Sep 2014; Accepted 27 Mar 2015; Published 7 May 2015. This work was supported by the Caltech/JPL president and director fund (PDF). A.A. was also supported by DARPA. Y.H. was supported by the JASSO fellowship and the 'Light-Material Interactions in Energy Conversion' Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Award no. DE-SC0001293. Alexander Ball was supported by the Summer Undergraduate Research Fellowship (SURF) at Caltech. The device nanofabrication was performed in the Kavli Nanoscience Institute at Caltech. We thank David Fattal and Sonny Vo for useful discussion. Author contributions: A.A., M.B. and A.F. conceived the experiment. A.A. and A.J.B. performed the FDTD simulations. A.A., Y.H. and M.B. fabricated the samples. A.A. performed the measurements, and analysed the data. A.A. and A.F. wrote the manuscript with input from all authors. Competing financial interests: The authors declare no competing financial interests.Attached Files
Submitted - 1410.8261v1.pdf
Supplemental Material - ncomms8069-s1.pdf
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Additional details
- Eprint ID
- 51173
- DOI
- 10.1038/ncomms8069
- Resolver ID
- CaltechAUTHORS:20141103-105332607
- Caltech/JPL President and Director Fund
- Defense Advanced Research Projects Agency (DARPA)
- JASSO Fellowship
- Department of Energy (DOE)
- DE-SC0001293
- Caltech Summer Undergraduate Research Fellowship (SURF)
- Created
-
2014-11-03Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Kavli Nanoscience Institute