Subdiffraction focusing with a long focal length using a terahertz-wave super-oscillatory lens

Autor:	Makoto Nakajima, Neville C. Luhmann, Makoto Ikeda, Anh-Vu Pham, Atsushi Mase, Ayato Iba, Calvin Domier
Rok vydání:	2021
Předmět:	Diffraction Depth of focus Materials science business.industry Terahertz radiation Atomic and Molecular Physics and Optics law.invention Lens (optics) Optics law Focal length Millimeter Spatial frequency business Image resolution
Zdroj:	Optics Letters. 46:4912
ISSN:	1539-4794 0146-9592
DOI:	10.1364/ol.434825
Popis:	This Letter describes a super-oscillatory lens (SOL), with concentric ring-type metallic slits photolithographically fabricated on a glass substrate, that can function at subterahertz frequencies. The SOL has been investigated both experimentally and theoretically and demonstrates a spatial resolution of 1.5 mm ( 0.5 λ ), which is 0.45 times the diffraction limit, with a focal length of 75 mm ( 25 λ ) at 100 GHz ( λ = 3 m m ). Furthermore, the depth of focus of the lens was measured to be 47 mm, which is 10.8 times larger than that of a conventional lens. This type of SOL, with subdiffraction focusing, is thus highly effective for use in industrial inspections with millimeter and terahertz waves.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b0931c98d34c09e02c2396f4c45d8f2c https://doi.org/10.1364/ol.434825 Zobrazit plný text záznamu