Zones optimized multilevel diffractive lens for polarization-insensitive light focusing

Bumin K. Yildirim, Emre Bor, Hamza Kurt, Mirbek Turduev*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


In this study, we present the numerical design and experimental demonstration of an all-dielectric low refractive index polarization-insensitive multilevel diffractive lens (MDL) at microwave frequencies. The proposed MDL structure is composed of concentric rings (zones) having different widths and heights. Here, the heights and widths of each dielectric concentric rings of lens structure are optimized by using the differential evolution (DE) algorithm to obtain the desired polarization-insensitive focusing performance. The DE method is incorporated with the three-dimensional finite-difference time-domain method to design an MDL structure and evaluate its wave focusing ability. The design frequency is fixed to 10 GHz and, at the design frequency, the DE method is applied to achieve light focusing with the full-width at half-maximum (FWHM) values of 0.654λ and 0.731λ for transverse-magnetic (TM) and transverse-electric (TE) polarizations, respectively, where λ is the wavelength of incident light in free space. Moreover, focusing efficiencies and numerical apertures are calculated as 60.3% and 0.853 at the design frequency, respectively, for both polarizations. Besides, experimental verifications of the numerical results are carried out in microwave regime where the MDL design is fabricated by 3D printing technology by using a polylactic acid material. In the microwave experiments, MDL focuses the TM and TE polarized waves at the focal distances of 71.82 mm and 69.3 mm with the FWHM values of 0.701λ and 0.887λ, respectively. We believe that the proposed design approach can be further expanded to design low refractive index lenses for visible and near-infrared wavelengths.

Original languageEnglish (US)
Article number495109
JournalJournal of Physics D: Applied Physics
Issue number49
StatePublished - Dec 2 2020

Bibliographical note

Funding Information:
This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under Project 116F182. H Kurt acknowledges partial support from the Turkish Academy of Sciences.

Publisher Copyright:
© 2020 IOP Publishing Ltd.


  • Diffractive lenses
  • Microwave experiment
  • Multilevel diffractive lens
  • Optimization
  • Polarization insensitive focusing

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films


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