Diffractive optical elements and quasioptical schemes for experiments on a high-power terahertz free-electron laser

Винокуров, Н.А.; Zhigach, S.A.; Knyazev, B. A.; Konysheva, A. V.; Кулипанов, Г.Н.; Merzhievsky, L.A.; Polskikh, I. A.; Cherkassky, V.S.

doi:10.1007/s11141-007-0071-3

Cited by 5 publications

(2 citation statements)

References 14 publications

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“…Two kinds of diffractive optical elements (figure 2) have been developed and tested using FEL radiation. Circular and elliptical brass mirrors with a parabolic profile of Fresnel zones [21,22] were fabricated for λ = 130 μm using a numerical control machine (NCM). The machinery-turned circular Fresnel mirror exhibited perfect focusing with a diffraction efficiency of about 100%, whereas the diffraction efficiency of a simple reflective Fresnel zone plate, produced by etching of a copper clad fiberglass board, was less than 10%.…”

Section: Instrumentation For Thz Beam Control and Transformationmentioning

confidence: 99%

Novosibirsk terahertz free electron laser: instrumentation development and experimental achievements

Knyazev

Кулипанов

Винокуров

2010

Meas. Sci. Technol.

124

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Nowadays, the Novosibirsk free electron laser (NovoFEL) is the most intense radiation source in the terahertz spectral range. It operates in the continuous mode with a pulse repetition rate of up to 11.2 MHz (5.6 MHz in the standard mode) and an average power of up to 500 W. The radiation wavelength can be precisely tuned from 120 to 240 mm with a relative line width of 0.3-1%, which corresponds to the Fourier transform limit for a micropulse length of 40-100 ps. The laser radiation is plane-polarized and completely spatially coherent. The radiation is transmitted to six user stations through a nitrogen-filled beamline. Characteristics of the NovoFEL radiation differ drastically from those of conventional low-power (and often broadband) terahertz sources, which enables obtaining results impossible with other sources, but necessitates the development of special experimental equipment and techniques. In this paper, we give a review of the instrumentation developed for control and detection of high-power terahertz radiation and for the study of interaction of the radiation with matter. Quasi-optic elements and systems, one-channel detectors, power meters, real-time imagers, spectroscopy devices and other equipment are described. Selected experimental results (continuous optical discharge, material and biology substance ablation, real-time imaging attenuated total reflection spectroscopy, speckle metrology, polarization rotation by an artificial chiral structure, terahertz radioscopy and imaging) are also presented in the paper. In the near future, after commissioning another four electron racetracks and two optical resonators, intense radiation in the range from 5 to 240 μm will be available for user experiments.

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Section: Instrumentation For Thz Beam Control and Transformationmentioning

confidence: 99%

Novosibirsk terahertz free electron laser: instrumentation development and experimental achievements

Knyazev

Кулипанов

Винокуров

2010

Meas. Sci. Technol.

124

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“…This reflection-type approach holds promise for THz beam-shaping and beam-focusing techniques as it allows creating purely flat, thin and lightweight reflectors capable of properly manipulating the wavefront through the control of the metasurface unit cell geometry. Due to relative simplicity in photolithographic fabrication, such kind of reflectors serve as an attractive alternative to the conventional diffractive optical elements (DOEs) based on cost-consuming structures with profiled surfaces 16 17 18 . In addition, working in reflection mode eliminates the Fresnel reflection loss and reduces the terahertz-material interaction.…”

mentioning

confidence: 99%

Planar Holographic Metasurfaces for Terahertz Focusing

Kuznetsov

Astafev

Beruete

et al. 2015

Sci Rep

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Scientists and laymen alike have always been fascinated by the ability of lenses and mirrors to control light. Now, with the advent of metamaterials and their two-dimensional counterpart metasurfaces, such components can be miniaturized and designed with additional functionalities, holding promise for system integration. To demonstrate this potential, here ultrathin reflection metasurfaces (also called metamirrors) designed for focusing terahertz radiation into a single spot and four spaced spots are proposed and experimentally investigated at the frequency of 0.35 THz. Each metasurface is designed using a computer-generated spatial distribution of the reflection phase. The phase variation within 360 deg is achieved via a topological morphing of the metasurface pattern from metallic patches to U-shaped and split-ring resonator elements, whose spectral response is derived from full-wave electromagnetic simulations. The proposed approach demonstrates a high-performance solution for creating low-cost and lightweight beam-shaping and beam-focusing devices for the terahertz band.

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