Subdiffraction focusing of total electric fields of terahertz wave

Yang, Mengyu; Ruan, Desheng; Du, Liang-Hui; Qin, Chunyan; Li, Zeyu; Lin, Cuiping; Chen, Gang; Wen, Zhongquan

doi:10.1016/j.optcom.2019.124764

Cited by 10 publications

(3 citation statements)

References 25 publications

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“…THz and acoustic superoscillations. The studies and development of applications of superoscillations is now extended to the terahertz electromagnetic frequency range 47,90,91 . A superoscillatory metalens with a resolution below the diffraction limit is demonstrated working around 0.327 THz 47 .…”

Section: Technologies Of Superoscillatory Lensesmentioning

confidence: 99%

Optical superoscillation technologies beyond the diffraction limit

Zheludev

Yuan

2021

Nat Rev Phys

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The phenomenon of optical superoscillations first introduced in 2006 (J. Phys. A 39, 6965, 2006) and experimentally identified shortly after (Appl. Phys. Lett. 90, 091119, 2007) describes the rapid subwavelength spatial variations of intensity and phase of light in complex electromagnetic fields formed by interference of several coherent waves. Its discovery stimulated the intense revision of the limits of classical electromagnetism in particular the study of structure of superoscillatory fields in free space including unlimitedly small energy hotspots, phase singularities, energy backflow, anomalously high wavevectors and their intriguing similarities to the evanescent plasmonic fields on metals. In recent years, the better understanding of superoscillatory light has led to the development of superoscillatory lensing, imaging and metrology technologies. Dielectric, metallic and metamaterial nanostructured superoscillatory lenses have been introduced that are able to create hotspots smaller than allowed by conventional lenses. Far-field, label-free non-intrusive deeply subwavelength superresolution imaging and metrology techniques that exploit high light localization and rapid variation of phase in superoscillatory fields have been developed including new approaches based on artificial intelligence. The present paper reviews the fundamental properties of superoscillatory optical fields and examines emerging technological applications of superoscillations.

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Section: Technologies Of Superoscillatory Lensesmentioning

confidence: 99%

Optical superoscillation technologies beyond the diffraction limit

Zheludev

Yuan

2021

Nat Rev Phys

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“…Sub-diffraction focusing was also achieved by two types of effective super-oscillatory lenses [ 76 , 77 , 78 ]. Photo-lithography was used to manufacture two structures: one being arrays of metaatoms and another consisting of many concentric rings.…”

Section: Efficient Focusing Of Thz Radiationmentioning

confidence: 99%

The Magic of Optics—An Overview of Recent Advanced Terahertz Diffractive Optical Elements

Siemion

2020

Sensors

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Diffractive optical elements are well known for being not only flat but also lightweight, and are characterised by low attenuation. In different spectral ranges, they provide better efficiency than commonly used refractive lenses. An overview of the recently invented terahertz optical structures based on diffraction design is presented. The basic concepts of structure design together with various functioning of such elements are described. The methods for structure optimization are analysed and the new approach of using neural network is shown. The paper illustrates the variety of structures created by diffractive design and highlights optimization methods. Each structure has a particular complex transmittance that corresponds to the designed phase map. This precise control over the incident radiation phase changes is limited to the design wavelength. However, there are many ways to overcome this inconvenience allowing for broadband functioning.

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“…A significant number of works in the field is devoted to development of lenses and diffraction gratings in the THz range. [2][3][4][5][6][7][8][9][10][11] However, the extensive application of coherent THz radiation requires for creating the components with wider functional capabilities. A lot of applications require the laser beam be focused into a given 2D and 3D region.…”

Section: Introductionmentioning

confidence: 99%

Control of tightly focused laser beams in the THz range

Degtyarev

Dubinin

Gurin

et al. 2021

Micro & Optical Tech Letters

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The possibility for control of tightly focused laser beams excited by the resonator modes of a THz laser based on a hollow circular dielectric waveguide is studied theoretically and experimentally. The wavelength of the radiation under study is 0.4326 mm corresponding to the generation line of the optically pumped HCOOH‐molecule THz laser. The focusing system is implemented by a short‐focus lens covered by absorbing masks in the central region. The focal area parameters were controlled by changing the size of the masks. The electric field components of the laser modes are calculated using the Rayleigh‐Sommerfeld integral transformations under non‐paraxial approximation. The use of absorbing masks made it possible to reduce the beam diameter in the focal region and increase the depth of focus of the linearly polarized EH11‐mode and azimuthally polarized TE01‐mode as well. In this case, despite of the presence of an absorbing mask, the distribution of the total field intensity of the TE01‐mode retained its annular shape, and the field maximum of the EH11‐mode is observed at center of the focal spot. The results of this work can be implemented in medical diagnostics, high‐speed communications, and environmental monitoring.

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Subdiffraction focusing of total electric fields of terahertz wave

Cited by 10 publications

References 25 publications

Optical superoscillation technologies beyond the diffraction limit

Optical superoscillation technologies beyond the diffraction limit

The Magic of Optics—An Overview of Recent Advanced Terahertz Diffractive Optical Elements

Control of tightly focused laser beams in the THz range

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