Abstract
The focusing properties of phase correcting Fresnel lenses with small values of focal length - to - diameter (FID) and with focal lengths of two wavelengths or less are investigated. For these lenses, the paraxial approximation for the Reyleigh resolution criterion is no longer valid. For Fresnel lenses designed with F/D < 0.2 and F ≤ λ, spatial resolutions of less than 0.5λ are possible, which is finer than what can typically be achieved for conventional (paraxial) designs. The spot beams in these cases are not quite axially symmetrical due to the presence of anti-symmetric field components, which vanish for larger values of F/D.
Original language | English |
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Title of host publication | IRMMW-THz 2006 - 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics |
Pages | 170 |
Number of pages | 1 |
DOIs | |
Publication status | Published - 2006 |
Externally published | Yes |
Event | IRMMW-THz 2006 - 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics - Shanghai, China Duration: 18 Sep 2006 → 22 Sep 2006 |
Conference
Conference | IRMMW-THz 2006 - 31st International Conference on Infrared and Millimeter Waves and 14th International Conference on Terahertz Electronics |
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Country | China |
City | Shanghai |
Period | 18.9.06 → 22.9.06 |
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering