Near-infrared subwavelength imaging using Al:ZnO-based near-field superlens

Li, Xiaoning; Jiao, Lei; Xu, Hua; Lu, Yuehui; Zhu, Cheng‐Ye; Duan, Juanmei; Zhang, Xianpeng; Dai, Ning; Song, Weijie

doi:10.1364/ome.6.003892

Cited by 8 publications

(2 citation statements)

References 32 publications

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“…Masouleh et al [12] showed that increasing the free electron concentration of the AZO will produce a negative dielectric constant in the infrared band with a low photon loss. Based on these, Li et al [13] developed a complex multilayer metalens based on the AZO that can achieve subwavelength imaging in the infrared region.…”

Section: Introductionmentioning

confidence: 99%

High efficient Al: ZnO based bifocus metalens in visible spectrum*

Wang¹,

Zeng²

2020

Chinese Phys. B

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The optical components of the visible light band are widely used in daily life and industrial development. However due to the serious loss of light and the high cost, the application is limited. The broadband gap metasurface will change this situation due to its low absorption and high efficiency. Herein, we simulate a size-adjustable metasurface of the Al doped ZnO (AZO) nanorod arrays based on finite difference time domain method (FDTD) which can realize the conversion of amplitude polarization and phase in the full visible band. The corresponding theoretical polarization conversion efficiency can reach as high as 91.48% (450 nm), 95.27% (530 nm), and 91.01% (65 nm). The modulation of focusing wavelength can be realized by directly adjusting the height of the AZO nanorod. The designed half-wave plate and metalens can be applied in the imaging power modulation halfwave conversion and enriching the spectroscopy.

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Section: Introductionmentioning

confidence: 99%

High efficient Al: ZnO based bifocus metalens in visible spectrum*

Wang¹,

Zeng²

2020

Chinese Phys. B

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“…In addition, AZO offers good chemical and mechanical stability as well as relative ease of fabrication and a broad range of doping [249,250,251]. Therefore, choosing AZO as the candidate material for our FSL study seemed logical and straightforward [252], as our research group had already developed expertise in AZO thin film deposition [253].…”

Section: Potential Alternative Plasmonic Materialsmentioning

confidence: 99%

Progress towards the realization of an optical Far-Field Superlens

Masouleh¹

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<p>Conventional optics suffer from a fundamental resolution limit due to the nature of light. The near-field superlens concept was introduced two decades ago, and its theory for enabling high resolution imaging is well-established now. Initially, this superlens, which has a simple setup, became a hot topic given the proposition of overcoming the diffraction limit. It has been demonstrated that a near-field superlens can reconstruct images using evanescent waves emanating from small objects by means of resonant excitations on the surface of the superlens. A modified version of the superlens named the far-field superlens is theorized to be able to project the near-field subwavelength information to the far-field region. By design, the far-field superlens is a near-field superlens with nanostructures added on top of it. These nanostructures, referred to as diffraction gratings help couple object information available in the evanescent waves to the far-field. Work reported in this thesis is divided to two major sections. The first describes the modelling technique that investigates the performance of a far-field superlens. This section focuses on evaluating the impact of the diffraction gratings geometry and the object size on the far-field superlens performance as well as the resulting far-field pattern. It was shown that a far-field superlens with a nanograting having a duty cycle of 40% to 50% produces the maximum intensity and contrast in the far-field interactions. For periodic rectangular objects, an inverse-trapezoidal nanograting was shown to provide the best contrast and intensity for far-field interactions. The minimal simulation domain to model a symmetric far-field superlens design was determined both in 2D and 3D. This input reduced the required modelling time and resources. Finally, a 3D far-field superlens model was proposed, and the effect of light polarization on the far-field pattern was studied. The second section of this thesis contains the experimental study that explores a new material as a potential candidate for the construction of far-field superlens. The material conventionally used for superlens design is silver, as its plasmonic properties are well-established. However, scaling down silver features to the nanoscale introduces fundamental fabrication challenges. Furthermore, silver oxidizes due to its reactions with sulphur compounds at ambient conditions, which means that operating a silver far-field superlens is only possible in a well-controlled environment. This disagrees with our proposed concept of a low-cost and robust superlens imaging device. On the other hand, highly doped semiconductors are emerging candidates for plasmonic applications due to the possibility of tuning their optical and electrical properties during the fabrication process. While the working principle of a superlens is independent of the plasmonic material of choice, every plasmonic material has a particular range of operating wavelengths. The pros and cons of each plasmonic material are usually identified once used experimentally. In this work, aluminium-doped zinc oxide was the proposed material of choice for the far-field superlens design. The second part of this thesis details the characterization results of the optical, electrical and structural properties of this proposed alternative. Our aluminium-doped zinc oxide samples were highly transparent for large parts of the spectrum. Their carrier concentration was of the order of 10+20 cm-3, and a resistivity of about 10-3 Ω.cm was achieved. The modelled dielectric permittivity for the studied samples showed a cross-over frequency in the near-infrared region, with the highest plasma frequency achieved in this study being 4710 cm-1.</p>

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Investigating the role of structural parameters of gold thin film nanohole arrays on the plasmonic phenomenon of extraordinary optical transmission

Tavakoli,

Shirpay

2024

J Comput Electron

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Near-infrared subwavelength imaging using Al:ZnO-based near-field superlens

Cited by 8 publications

References 32 publications

High efficient Al: ZnO based bifocus metalens in visible spectrum*

High efficient Al: ZnO based bifocus metalens in visible spectrum*

Progress towards the realization of an optical Far-Field Superlens

Investigating the role of structural parameters of gold thin film nanohole arrays on the plasmonic phenomenon of extraordinary optical transmission

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