Imaging of THz waves in 2D photonic crystal structures embedded in a slab waveguide

Peier, Peter; Merbold, Hannes; Pahinin, V.; Nelson, Keith A.; Feurer, Thomas

doi:10.1088/1367-2630/12/1/013014

Cited by 15 publications

(15 citation statements)

References 37 publications

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“…We believe that mapping the dispersion surfaces of 2D phononic crystals should yield even more interesting results. The approach used in this work may be extended beyond phononic crystals: for example, the transient grating technique has been used to measure the dispersion of phonon-polaritons in LiNbO 3 and LiTaO 3 [25]; thus it may prove instrumental for studying the band structure of photonic crystals in the THz range fabricated in these materials [26].…”

Section: Discussionmentioning

confidence: 99%

Mapping the band structure of a surface phononic crystal

Maznev¹,

Wright²,

Matsuda³

2011

New J. Phys.

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Abstract. We map the band structure of surface acoustic modes of a periodic array of copper lines embedded in a SiO 2 film on a silicon substrate by means of the laser-induced transient grating technique. A detailed map of the lowest sheet of the ω(k) surface and partial maps of two higher-order sheets are obtained. We discuss the topology of the ω(k) surface and explain how it arises from the Rayleigh and Sezawa modes of the film/substrate system. In the vicinity of the bandgap formed at the Brillouin zone boundary, the first and second dispersion sheets take the form of a saddle and a bowl, respectively, in agreement with a weak perturbation model. The shape of the third dispersion sheet, however, appears to defy expectations based on the perturbation approach. In particular, it contains minima located off the symmetry directions, which implies the existence of zero group velocity modes with an obliquely directed wavevector.

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Section: Discussionmentioning

confidence: 99%

Mapping the band structure of a surface phononic crystal

Maznev¹,

Wright²,

Matsuda³

2011

New J. Phys.

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“…We can also clearly see evidence of dispersion as different frequency components propagate at different speeds. The THz waves in the PhC also travel at a different velocity compared to the unstructured slab [33], further demonstrating different dispersion relations.…”

Section: Visualizing Waves In Phcmentioning

confidence: 99%

“…The platform naturally lends itself to the fabrication of PhC slabs because the high dielectric contrast between the host materials (ε eo ≈ 26 for LiNbO 3 and ε eo ≈ 38 for LiTaO 3 at THz frequencies [1]) and air results in extremely efficient scattering at the interfaces. PhC slabs have been fabricated on the polaritonics system in the past [33,34], but it was not possible to measure the fields inside the PhC because of insufficient imaging capabilities and sample preparation techniques. Recently, improved imaging methods [8] have enabled direct observation of the fields within densely machined structures such as the PhCs.…”

Section: Introductionmentioning

confidence: 99%

Direct experimental visualization of waves and band structure in 2D photonic crystal slabs

et al. 2014

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We demonstrate for the first time the ability to perform time resolved imaging of terahertz (THz) waves propagating within a photonic crystal (PhC) slab. For photonic lattices with different orientations and symmetries, we used the electrooptic effect to record the full spatiotemporal evolution of THz fields across a broad spectral range spanning the photonic band gap. In addition to revealing real-space behavior, the data let us directly map the band diagrams of the PhCs. The data, which are in good agreement with theoretical calculations, display a rich set of effects including photonic band gaps, eigenmodes and leaky modes.S Online supplementary data available from stacks.iop.org/NJP/16/053003/ mmedia

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“…Considering a 2D system reduces the computational cost of the numerical simulations. Also, the structure is compatible with some experiments that directly measure field [43]. As a further step, it would be interesting to apply the circular Bessel density function to a polarized field measurement in 3D random media.…”

Section: E Discussionmentioning

confidence: 70%

“…Theoretically, it is vital in the understanding of the formation of freak waves [44] and can potentially motivate the development of a moment theorem analogous to that developed for Gaussian statistics [45]. Experimentally, it can provide the theory for experiments that directly measure field [43], facilitate random media characterization when designing highly directional random lasers [46,47] and compact spectrometers [48], as well as imaging within and through randomly scattering media.…”

Section: Resultsmentioning

confidence: 99%

Circular Bessel statistics: derivation and application to wave propagation in random media

2014

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We present a family of circular Bessel probability density functions that are capable of describing the intensity, amplitude, and field statistics of waves in any random medium, with only the assumption of circularity. The well-known zero-mean circular Gaussian statistics break down in the Anderson localization and the weakly scattering regimes, where the field can no longer be regarded as the sum of a multitude of independent random phasors. We find that in such scenarios circular Bessel statistics apply because the field can be modeled as a random phasor sum with a random number of contributing phasors. The validity of our density functions is verified through numerical simulations of electromagnetic waves propagating in 2D random media. Having a set of density functions that work in all scattering regimes provides a framework for modeling wave propagation in random media, facilitating random media characterization, imaging in and through scatter, and random laser design.

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Imaging of THz waves in 2D photonic crystal structures embedded in a slab waveguide

Cited by 15 publications

References 37 publications

Mapping the band structure of a surface phononic crystal

Mapping the band structure of a surface phononic crystal

Direct experimental visualization of waves and band structure in 2D photonic crystal slabs

Circular Bessel statistics: derivation and application to wave propagation in random media

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