Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group

Reflective metasurface lens with an elongated needle-shaped focus

Abstract

Novel multifocal flat metasurface (MS) lenses are developed using two techniques: (i) polarization diversity, and (ii) annular segmentation of the lens aperture. The polarization-diversity technique enables overall lens aperture reuse, thus doubling the number of foci through the simultaneous focusing of two orthogonal linearly polarized incident beams at two distinct foci using the lens aperture. The annular-segmentation technique, on the other hand, is independent of incident beam polarization and is only based on dividing the lens aperture into concentric annular segments that converge different portions of the illuminating beam at different foci. The total number of foci can be further increased by combining the polarization-diversity and the annular-segmentation techniques. Subsequently, the concept of multifocality is further extended to design a novel flat lens with an overall single needle-like focal region with elongated depth of focus (DOF) without loss of lateral resolution. To this goal, we design a multifocal lens with overlapping profiles of foci superposed into a single elongated needle-shaped focal region. Using the combination of polarization-diversity and annular-segmentation techniques, we develop a novel MS flat lens made of Y-shaped nanoantennas, whose polarization-dependent reflection phase and amplitude can be controlled independently via their geometrical parameters. Via numerical calculations, we demonstrate that the proposed MS lens has an overall single focal region with an extremely long DOF of about 74.1λ, a lateral full width at half maximum varying in the range of 1.37λ to 2.8λ, and a numerical aperture of about 0.26 (considering the center of the focal region as the effective focal point). Here, the MS lens’s capability to synthesize extremely long DOF is conceptually demonstrated without resorting to time-consuming and complicated wavefront synthesis methods. The engineering of focal intensity profiles with flat MSs may introduce significant advancement in nanoimaging, many areas of microscopy, and ophthalmic applications.

© 2017 Optical Society of America

Full Article  |  PDF Article
More Like This
Generation of needle beams through focusing of azimuthally polarized vortex beams by polarization-insensitive metasurfaces

Zhe Shen, Rui Li, Shijie Huang, Baifu Zhang, and Qinnan Chen
J. Opt. Soc. Am. B 38(6) 1869-1876 (2021)

Thin anisotropic metasurfaces for simultaneous light focusing and polarization manipulation

Mehdi Veysi, Caner Guclu, Ozdal Boyraz, and Filippo Capolino
J. Opt. Soc. Am. B 32(2) 318-323 (2015)

Birefringent transmissive metalens with an ultradeep depth of focus and high resolution

Jiaran Qi, Yongheng Mu, Shaozhi Wang, Zhiying Yin, and Jinghui Qiu
Photon. Res. 9(3) 308-316 (2021)

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Figures (7)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Equations (2)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All Rights Reserved