Flat Low-Loss Silicon Gradient Index Lens for Millimeter and Submillimeter Wavelengths

  • F. DefranceEmail author
  • C. Jung-Kubiak
  • S. Rahiminejad
  • T. Macioce
  • J. Sayers
  • J. Connors
  • S. J. E. Radford
  • G. Chattopadhyay
  • S. R. Golwala


We present the design, simulation, and planned fabrication process of a flat high resistivity silicon gradient index (GRIN) lens for millimeter and submillimeter wavelengths with very low absorption losses. The gradient index is created by sub wavelength holes whose size increases with the radius of the lens. The effective refractive index created by the subwavelength holes is constant over a very wide bandwidth, allowing the fabrication of achromatic lenses up to submillimeter wavelengths. The designed GRIN lens was successfully simulated and shows an expected efficiency better than that of a classic silicon plano-concave spherical lens with approximately the same thickness and focal length. Deep reactive ion etching (DRIE) and wafer-bonding of several patterned wafers will be used to realize our first GRIN lens prototype.


Lens Gradient index Silicon GRIN Subwavelength DRIE THz 



This work was funded by NASA (Grant NNX15AE01G). The Caltech/JPL President’s and Director’s Research Fund proposal was recently successful and will allow us to continue this work. SBIR and APRA proposals are currently under review.


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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Division of Physics, Mathematics, and AstronomyCalifornia Institute of TechnologyPasadenaUSA
  2. 2.Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaUSA
  3. 3.NASA Goddard Space Flight CenterGreenbeltUSA
  4. 4.Smithsonian Astrophysical ObservatorySubmillimeter ArrayHiloUSA

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