Document Type

Article

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Disciplines

Electrical and Computer Engineering | Electromagnetics and Photonics | Optics | Other Physical Sciences and Mathematics | Physical Sciences and Mathematics | Plasma and Beam Physics

CIT Disciplines

2.2 ELECTRICAL, ELECTRONIC, INFORMATION ENGINEERING

Publication Details

Computer Optics

Abstract

Using e-beam lithography, a 16-sector spiral metalens was fabricated in an amorphous silicon, capable of converting linearly polarized incident light into an azimuthally polarized optical vortex. When illuminated by a 633-nm linearly polarized laser beam, the metalens generated a near-surface subwavelength focal spot equal to 0.75 of the incident wavelength at full-width of half-maximum intensity. The focusing performance of the spiral metalens was numerically shown to be sensitive to the deviation of the factual microrelief from the calculated height. For the designed microrelief height, a circularly polarized incident beam was focused into a bright ring with a reverse energy flow occurring at its center. For the microrelief height other than the designed one, the energy backflow effect did not occur.

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