Electromagnetic Wave Propagation Close to Microstructures Studied by Time and Phase-Resolved THz Near-Field Imaging

Walther, Markus; Bitzer, Andreas

doi:10.1007/s10762-011-9772-y

Cited by 7 publications

(3 citation statements)

References 24 publications

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“…For this purpose, we use a terahertz near-field microscope, which is capable of mapping the field distribution with a spatial resolution well below the diffraction limit [48,49]. Such a system has been used to investigate the near fields of sub-wavelength-sized structures [48,50], and also to study wave propagation along surfaces or in free space [51,52]. Figure 1 illustrates the near-field microscope, which relies on the terahertz time-domain spectroscopy approach.…”

Section: Methodsmentioning

confidence: 99%

Gouy phase shift of a tightly focused, radially polarized beam

Kaltenecker

König-Otto

Mittendorff

et al. 2016

Optica

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Radially polarized beams represent an important member of the family of vector beams, in particular due to the possibility of using them to create strong and tightly focused longitudinal fields, a fundamental property that has been exploited by applications ranging from microscopy to particle acceleration. Since the properties of such a focused beam are intimately related to the Gouy phase shift, proper knowledge of its behavior is crucial. Terahertz microscopic imaging is used to extract the Gouy phase shift of the transverse and longitudinal field components of a tightly focused, radially polarized beam. Since the applied terahertz time-domain approach is capable of mapping the amplitude and phase of an electromagnetic wave in space, we are able to directly trace the evolution of the geometric phase as the wave propagates through the focus. We observe a Gouy phase shift of 2π for the transverse and of π for the longitudinal component. Our experimental procedure is universal and may be applied to determine the geometric phase of other vector beams, such as optical vortices, or even arbitrarily shaped and polarized propagating waves.

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Section: Methodsmentioning

confidence: 99%

Gouy phase shift of a tightly focused, radially polarized beam

Kaltenecker

König-Otto

Mittendorff

et al. 2016

Optica

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“…The near-field images of the output field profiles of the suspended core fibers in Fig. 7 were obtained using a terahertz near-field microscopy system based on the implementation of photoconductive antennae acting first as the coherent xpolarized THz pulse source and as a near-field probe (see Fig 11) [34,35]. This powerful characterization technique provides subwavelength spatial resolution (~λ/20) images with time-frames of sub-picosecond temporal precision.…”

Section: Thz Near-field Imaging For Fiber Mode Profilingmentioning

confidence: 99%

Polymer microstructured optical fibers for terahertz wave guiding

et al. 2011

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We outline the most recent technological advancements in the design, fabrication and characterization of polymer microstructured optical fibers (MOFs) for applications in the terahertz waveband. Focusing on specific experimental demonstrations, we show that polymer optical fibers provide a very flexible route towards THz wave guiding. Crucial incentives include the large variety of the low-cost and relatively low absorption loss polymers, the facile fiber preform fabrication by molding, drilling, stacking and extrusion, and finally, the simple fabrication through fiber drawing at low forming temperatures.

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“…Application of the near-field scanning probe microscopy method at terahertz (THz) frequencies (λ = 30-1000 µm) has enabled studies of a range of scientific questions [1]. The method allows spatial resolution to be improved beyond the diffraction limit, as well as detecting evanescent components of the THz field [1][2][3][4][5][6][7][8]. This capability is particularly suitable for studies of electromagnetic fields in the near-field region of antennas.…”

Section: Introductionmentioning

confidence: 99%

Modelling of surface waves on a THz antenna detected by a near-field probe

Natrella¹,

Mitrofanov²,

Mueckstein³

et al. 2012

Opt. Express

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We have modelled the experimental system based on the sub-wavelength aperture probe employed in our previous work for terahertz (THz) surface plasmon wave imaging on a bowtie antenna. For the first time we demonstrate the accuracy of the proposed interpretation of the images mapped by the probe. The very good agreement between numerical and experimental results proves that the physical quantity detected by the probe is the spatial derivative of the electric field normal component. The achieved understanding of the near-field probe response allows now a correct interpretation of the images and the distribution of the electric field to be extracted. We have also carried out the first assessment of the probe invasiveness and found that the pattern of the surface plasmon wave on the antenna is not modified significantly by the proximity of the probe. This makes the experimental system an effective tool for near-field imaging of THz antennas and other metallic structures.

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Electromagnetic Wave Propagation Close to Microstructures Studied by Time and Phase-Resolved THz Near-Field Imaging

Cited by 7 publications

References 24 publications

Gouy phase shift of a tightly focused, radially polarized beam

Gouy phase shift of a tightly focused, radially polarized beam

Polymer microstructured optical fibers for terahertz wave guiding

Modelling of surface waves on a THz antenna detected by a near-field probe

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