Three-dimensional direct observation of Gouy phase shift in a terajet produced by a dielectric cuboid

Pham, Hai Huy Nguyen; Hisatake, Shintaro; Minin, Igor V.; Minin, Oleg V.; Nagatsuma, Tadao

doi:10.1063/1.4949014

Cited by 24 publications

(11 citation statements)

References 19 publications

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“…This result, when associated with the result previously reported in Ref. 28, indicates that this enhancer can enhance the spatial resolution into the subwavelength region by being placed at the focal point of the focusing device, regardless of its NA value. Subwavelength-resolution imaging based on the terajet generated by the enhancer is also demonstrated through nondestructive imaging of both an integrated-circuit (IC) card and an aluminum plate with subwavelength trenches.…”

Section: Introductionsupporting

confidence: 88%

“…The FWHM obtained with the enhancer is even better than that obtained by a focusing device with an ideal maximum value of the NA in air (NA = 1, FWHM limit = 0.67λ). Associating this result with the result previously obtained with terajets generated under planar incidence (FWHM = 0.6λ), 28 an NA = 0 focusing device, indicates that mesoscale dielectric cubes can enhance the spatial resolution to the subwavelength region by simply being placed at the focused imaging points of CW-THz imaging systems with different values of the NA. A slight misalignment of the enhancer position (about 0.2λ) when placing the enhancer at the focused imaging point shows no significant effect on the subwavelength FWHM of the hotspot.…”

Section: Characterization Of the Generated Terajetsupporting

confidence: 79%

“…23 The generation of terajets from the cuboid under planar illumination, which can be considered as an NA = 0 focusing device with the focal point at infinity, has been experimentally confirmed and verified in the THz frequency band; the obtained FWHM was 0.6λ. 28 The influence of the tangent losses in the cuboid's dielectric material and the wide angular focusing capabilities has been studied numerically. 29,30 In this study, we establish, for the first time, that the mesoscale dielectric cube, the enhancer, can be exploited as a novel resolution enhancer by simply placing it at the focused imaging points of a continuous wave (CW)-THz imaging system of arbitrary types.…”

Section: Introductionmentioning

confidence: 99%

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Enhancement of spatial resolution of terahertz imaging systems based on terajet generation by dielectric cube

et al. 2017

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The terahertz (THz, 0.1–10 THz) region has been attracting tremendous research interest owing to its potential in practical applications such as biomedical, material inspection, and nondestructive imaging. Those applications require enhancing the spatial resolution at a specific frequency of interest. A variety of resolution-enhancement techniques have been proposed, such as near-field scanning probes, surface plasmons, and aspheric lenses. Here, we demonstrate for the first time that a mesoscale dielectric cube can be exploited as a novel resolution enhancer by simply placing it at the focused imaging point of a continuous wave THz imaging system. The operating principle of this enhancer is based on the generation—by the dielectric cuboid—of the so-called terajet, a photonic jet in the THz region. A subwavelength hotspot is obtained by placing a Teflon cube, with a 1.46 refractive index, at the imaging point of the imaging system, regardless of the numerical aperture (NA). The generated terajet at 125 GHz is experimentally characterized, using our unique THz-wave visualization system. The full width at half maximum (FWHM) of the hotspot obtained by placing the enhancer at the focal point of a mirror with a measured NA of 0.55 is approximately 0.55λ, which is even better than the FWHM obtained by a conventional focusing device with the ideal maximum numerical aperture (NA = 1) in air. Nondestructive subwavelength-resolution imaging demonstrations of a Suica integrated circuit card, which is used as a common fare card for trains in Japan, and an aluminum plate with 0.63λ trenches are presented. The amplitude and phase images obtained with the enhancer at 125 GHz can clearly resolve both the air-trenches on the aluminum plate and the card’s inner electronic circuitry, whereas the images obtained without the enhancer are blurred because of insufficient resolution. An increase of the image contrast by a factor of 4.4 was also obtained using the enhancer.

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Section: Introductionsupporting

confidence: 88%

Section: Characterization Of the Generated Terajetsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

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Enhancement of spatial resolution of terahertz imaging systems based on terajet generation by dielectric cube

et al. 2017

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“…Compared with the same sized spherical particle-lens or other particle-lenses with the arbitrary shapes, cuboid particle-lens or SIL commonly stimulates a longer photonic jet with a more circular profile in the radial direction [21], and the corresponding focusing properties in THz band were investigated in the previous publications [22,23]. In this letter, we experimentally verified the effect of anomalous amplitude mask apodization that simultaneously delivers intensity enhancement and focus narrowing to the photonic jet in millimetre band for the first time, which is also a successful validation of scale effect for our previous simulation of the pupil-masked SIL functioning in the optical band.…”

Section: Introductionmentioning

confidence: 99%

A Millimetre-Wave Cuboid Solid Immersion Lens with Intensity-Enhanced Amplitude Mask Apodization

Yue

Yan

Monks

et al. 2018

J Infrared Milli Terahz Waves

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Photonic jet is a narrow, highly intensive, weak-diverging beam propagating into a background medium, and can be produced by a cuboid solid immersion lens (SIL) in both transmission and reflection modes. Amplitude mask apodization is an optical method to further improve the spatial resolution of a SIL imaging system via reduction of waist size of photonic jet, but always leading to intensity-loss due to central masking of the incoming plane wave. In this letter, we report a particularly sized millimetre-wave cuboid SIL with the intensity-enhanced amplitude mask apodization for the first time. It is able to simultaneously deliver extra intensity enhancement and waist narrowing to the produced photonic jet. Both numerical simulation and experimental verification of the intensity-enhanced apodization effect are demonstrated using a copper-masked Teflon cuboid SIL with 22 mm side length under radiation of a plane wave with 8 mm wavelength. Peak intensity enhancement and the lateral resolution of the optical system increase by about 36.0 % and 36.4 % in this approach, respectively.

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“…Recently, we proposed a mesoscopic dielectric cuboid antenna (DCA) operating at 24 GHz and measured its fundamental characteristics (Samura et al, 2019). The proposed DCA is based on the terajet effect (Pacheco-Peña et al, 2014;Nguyen Pham et al, 2016), and exhibits a simple-structure with a size of 1.2λ × 1.2λ × 1.36λ. At 24 GHz, the DCA characteristics were experimentally demonstrated, exhibiting a 14.22 dBi gain and 21 and 34% narrower beamwidths in the E-and H-planes, respectively, compared with those of a horn antenna with the same dimensions.…”

Section: Introductionmentioning

confidence: 99%

Short-Range Wireless Transmission in the 300 GHz Band Using Low-Profile Wavelength-Scaled Dielectric Cuboid Antennas

et al. 2021

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A short-range terahertz (THz) wireless transmission in the 300 GHz band is demonstrated using low-profile wavelength-scaled dielectric transmitting and receiving cuboid antennas (DCAs). These dielectric cuboid antennas are made of polytetrafluoroethylene with dimensions of approximately 1.2 mm × 1.2 mm × 1.3 mm. The near-field pattern of a DCA at 300 GHz was measured using an electro-optic sensing technique, and its far-field pattern characterization was based on the near-field to far-field transformation. The measured antenna gain was 15.06 ± 0.06 dBi. By employing DCAs as transmitting and receiving antennas, a 17.5 Gbps data transmission rate at distances of approximately 200 and 50 mm with bit error rates of 3.31 × 10–3 and 7.51 × 10–7 respectively, is demonstrated. The proposed mesoscopic scale DCA is a promising antenna type in intra-device communications and Kiosk download applications for future mobile devices operating in the 300 GHz band.

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Three-dimensional direct observation of Gouy phase shift in a terajet produced by a dielectric cuboid

Cited by 24 publications

References 19 publications

Enhancement of spatial resolution of terahertz imaging systems based on terajet generation by dielectric cube

Enhancement of spatial resolution of terahertz imaging systems based on terajet generation by dielectric cube

A Millimetre-Wave Cuboid Solid Immersion Lens with Intensity-Enhanced Amplitude Mask Apodization

Short-Range Wireless Transmission in the 300 GHz Band Using Low-Profile Wavelength-Scaled Dielectric Cuboid Antennas

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