Journal Publications by Imre.dr. Teng Jing Hua
Recent developments have shown that light’s orbital angular momentum (OAM) can be harnessed for a... more Recent developments have shown that light’s orbital angular momentum (OAM) can be harnessed for a diversity of emerging applications and generated by miniaturized OAM generators. Nanostructured flat logarithmic-spiral zone
plates (LSZPs) are proposed to produce as well as focus optical vortices with a long focal depth in the broadband visible range. Topologically breaking the in-plane symmetry, this nanoengineered LSZP continuously modulates both
amplitude and phase in the diffraction field to shape twisted focusing of the optical vortex beam, which is microscopically confined and spatially spiraling with variant crescent-shaped transverse intensity profiles. Owing to its rich structural degree of freedom upon aperiodic and continuously variant features, the LSZP provides a compact solution to generate and control optical vortices carrying scalable OAM and highly concentrated photons with a high transmission efficiency of ∼22%. This can offer new opportunities for 3D light shaping,
Papers by Imre.dr. Teng Jing Hua
arXiv (Cornell University), Mar 20, 2023
Planar lenses with optimized but disordered structures can focus light beyond the diffraction lim... more Planar lenses with optimized but disordered structures can focus light beyond the diffraction limit. However, these disordered structures have inevitably destroyed wide-field imaging capability, limiting their applications in microscopy. Here we introduce information entropy S to evaluate the disorder of an objective chip by using the probability of its structural deviation from standard Fresnel zone plates. Inspired by the theory of entropy change, we predict an equilibrium point S0=0.5 to balance wide-field imaging (theoretically evaluated by the Strehl ratio) and subdiffraction-limit focusing. To verify this, a NA=0.9 objective chip with a record-long focal length of 1 mm is designed with S=0.535, which is the nearest to the equilibrium point among all reported planar lenses. Consequently, our fabricated chip can focus light with subdiffraction-limit size of 0.44λ and image fine details with spatial frequencies up to 4000 lp/mm in experiment. These unprecedented performances enable ultracompact reflective confocal microscopy for superresolution imaging.
Optics Express, 2004
The propagation of surface plasmon polaritons on metallic waveguides adjacent to a gain medium is... more The propagation of surface plasmon polaritons on metallic waveguides adjacent to a gain medium is considered. It is shown that the presence of the gain medium can compensate for the absorption losses in the metal. The conditions for existence of a surface plasmon polariton and its lossless propagation and wavefront behavior are derived analytically for a single infinite metal-gain boundary. In addition, the cases of thin slab and stripe geometries are also investigated using finite element simulations. The effect of a finite gain layer and its distance from the SPP waveguide is also investigated. The calculated gain requirements suggest that lossless gainassisted surface plasmon polariton propagation can be achieved in practice for infrared wavelengths.
Renewable & Sustainable Energy Reviews, 2023
Advanced Functional Materials, May 24, 2016
Compact and miniaturized devices with flexible functionalities are always highly demanded in opti... more Compact and miniaturized devices with flexible functionalities are always highly demanded in optical integrated systems. Plasmonic nanosieve has been successfully harnessed as an ultrathin flat platform for complex manipulation of light, including holography, vortex generation and non-linear processes. Compared with most of reported single-functional devices, multifunctional nanosieves might find more complex and novel applications across nano-photonics, optics and nanotechnology. Here, we experimentally demonstrate a promising roadmap for nanosieve-based helical devices, which achieves full manipulations of optical vortices, including its generation, hybridization, spatial multiplexing, focusing and non-diffraction propagation etc., by controlling the geometric phase of spin light via over 121 thousands of spatially-rotated nanosieves. Thanks to such spin-conversion nanosieve helical elements, it is no longer necessary to employ the conventional two-beam interferometric measurement to characterize optical vortices, while the interference can be realized natively without changing any parts of the current setup. The proposed strategy makes the far-field manipulations of optical orbital angular momentum within an ultrathin interface viable and bridges singular optics and integrated optics. In addition, it enables more unique extensibility and flexibility in versatile optical elements than traditional phase-accumulated helical optical devices.
Advanced Materials, Feb 2, 2016
Applied Physics Letters, Nov 7, 2016
Conventional optical spanners based on free-space focused vortex beams are very difficult to mani... more Conventional optical spanners based on free-space focused vortex beams are very difficult to manipulate subwavelength objects due to the diffraction limit, while optical subwavelength spanners are not explored. Evanescent wave is one potential tool to realize subwavelength trapping. By combining vortex with evanescent field, we find that the evanescent vortex can function as an optical subwavelength spanner. We investigate the factors that will affect the generation/function of this subwavelength spanner, including numerical aperture and topological charge. Further, by calculating the optical force and potential on the illuminated objects, we have demonstrated that the evanescent optical vortex field is able to trap 200 nm polystyrene spherical particles and to rotate them around the ring-shaped field at the same time, making it a subwavelength optical spanner. This mechanism can be used as a tool to study the behaviour of very small objects in physics and biology.
Optics Express, 2020
Optical metasurface based refractive index (RI) sensors find applications in chemical, environmen... more Optical metasurface based refractive index (RI) sensors find applications in chemical, environmental, biomedical, and food processing industries. The existing RI sensors based on metals suffer from the plasmonic loss in the optical regime; in contrast, those based on Fano-type resonances generated by dielectric materials are either polarization-sensitive or are based on complex geometrical structures prone to fabrication imperfections that can lead to severe performance degradation. Here, we demonstrate that careful engineering of resonance modes in dielectric metasurfaces based on simple symmetric meta-atoms can overcome these limitations. More specifically, we have designed low-loss high-performance RI sensors using all-dielectric metasurfaces composed of TiO2 based nanostructures of three different shapes (i.e., cylindrical, square and elliptical) operating at near-infrared (NIR) wavelengths, which are robust against the perturbations of geometric parameters. In terms of physics,...
Angewandte Chemie International Edition, 2020
Ligand‐induced surface restructuring with heteroatomic doping is used to precisely modify the sur... more Ligand‐induced surface restructuring with heteroatomic doping is used to precisely modify the surface of a prototypical [Au25(SR1)18]− cluster (1) while maintaining its icosahedral Au13 core for the synthesis of a new bimetallic [Au19Cd3(SR2)18]− cluster (2). Single‐crystal X‐ray diffraction studies reveal that six bidentate Au2(SR1)3 motifs (L2) attached to the Au13 core of 1 were replaced by three quadridentate Au2Cd(SR2)6 motifs (L4) to create a bimetallic cluster 2. Experimental and theoretical results demonstrate a stronger electronic interaction between the surface motifs (Au2Cd(SR2)6) and the Au13 core, attributed to a more compact cluster structure and a larger energy gap of 2 compared to that of 1. These factors dramatically enhance the photoluminescence quantum efficiency and lifetime of crystal of the cluster 2. This work provides a new route for the design of a wide range of bimetallic/alloy metal nanoclusters with superior optoelectronic properties and functionality.
Nature Communications, 2019
Metasurfaces as artificially nanostructured interfaces hold significant potential for multi-funct... more Metasurfaces as artificially nanostructured interfaces hold significant potential for multi-functionality, which may play a pivotal role in the next-generation compact nano-devices. The majority of multi-tasked metasurfaces encode or encrypt multi-information either into the carefully tailored metasurfaces or in pre-set complex incident beam arrays. Here, we propose and demonstrate a multi-momentum transformation metasurface (i.e., meta-transformer), by fully synergizing intrinsic properties of light, e.g., orbital angular momentum (OAM) and linear momentum (LM), with a fixed phase profile imparted by a metasurface. The OAM meta-transformer reconstructs different topologically charged beams into on-axis distinct patterns in the same plane. The LM meta-transformer converts red, green and blue illuminations to the on-axis images of “R”, “G” and “B” as well as vivid color holograms, respectively. Thanks to the infinite states of light-metasurface phase combinations, such ultra-compact ...
Scientific Reports, 2019
We report a simple, single-cycle synthetic method for forming highly-crystalline, micron-sized mo... more We report a simple, single-cycle synthetic method for forming highly-crystalline, micron-sized monolayer domains of phase-pure MoS2. This method combines liquid chemistry with discrete, layer-by-layer deposition from a novel Mo precursor. Single-crystalline MoS2 with domain sizes up to 100 μm have been obtained and characterised by optical and electron microscopy as well as Raman and photoluminescence spectroscopy.
Laser & Photonics Reviews, 2019
Functionalization of quantum dots to induce circular dichroism as well as the direct emission of ... more Functionalization of quantum dots to induce circular dichroism as well as the direct emission of circularly polarized light is the subject of intensive studies for the obvious importance not only in practical applications but also in gaining a deeper understanding of quantum semiconductor heterostructures. In this work, remarkable chiral features in achiral CdSe/ZnS colloidal quantum dots (CQDs) induced by plasmonic chiral metasurfaces are reported. Not only giant circular dichroism, but also a high degree of circular polarization in the light emitted by the CQDs hybridized with the chiral metasurfaces is observed. By probing the response of CQDs combined with tunable chiral metasurfaces, it is shown that the induced chiral features are closely linked to the correlation between the absorption bands of CQDs and the chiral bands of the metasurfaces. The findings indicate that plasmonic chiral metasurface is an effective medium in reshaping CQDs with useful chiral properties.
Advanced Optical Materials, 2018
Researches in metamaterials and metasurfaces have significant impact on development of terahertz ... more Researches in metamaterials and metasurfaces have significant impact on development of terahertz optics and progression of terahertz science and technologies. Further advancement of terahertz systems demands efficient and versatile tunable and reconfigurable metadevices for manipulating various properties of terahertz radiation. Here an electrically and thermally tunable silicon metasurface for broadband terahertz antireflection application is demonstrated. The silicon metasurface is composed by interdigitated p–n junctions fabricated using a completely complementary metal‐oxide‐semiconductor (CMOS) compatible process in a silicon photonics foundry. It is atomically smooth without any physically etched pattern nor metal antennas. By supplying bias voltage to the p–n junctions, the complex reflection coefficient of the silicon metasurface is continuously tuned between negative and positive values. Complete antireflection condition can be precisely achieved, represented by the vanishi...
Science advances, 2017
In the era of big data, there exists a growing gap between data generated and storage capacity us... more In the era of big data, there exists a growing gap between data generated and storage capacity using two-dimensional (2D) magnetic storage technologies (for example, hard disk drives), because they have reached their performance saturation. 3D volumetric all-optical magnetic holography is emerging rapidly as a promising road map to realizing high-density capacity for its fast magnetization control and subwavelength magnetization volume. However, most of the reported light-induced magnetization confronts the problems of impurely longitudinal magnetization, diffraction-limited spot, and uncontrollable magnetization reversal. To overcome these challenges, we propose a novel 3D light-induced magnetic holography based on the conceptual supercritical design with multibeam combination in the 4π microscopic system. We theoretically demonstrate a 3D deep super-resolved [Formula: see text] purely longitudinal magnetization spot by focusing six coherent circularly polarized beams with two oppo...
Applied Physics Letters, 2017
Manipulating light spin (or circular polarization) is an important research field and may find br... more Manipulating light spin (or circular polarization) is an important research field and may find broad applications from sensors, display technology, to quantum computing and communication. To this end, planar metasurfaces with larger circular dichroism are strongly demanded. However, current planar chiral metasurface structures suffer from either fabrication challenge, especially from near-infrared to visible spectrum, or insufficient circular dichroism. Here, we report a chiral metasurface composed of achiral nanoholes which allow for precisely creating apexes in the designed structure. Our investigation indicates that the apexes act as super chiral hot spots and enable the highly concentrated near-field optical chirality leading to a remarkable enhancement of circular dichroism in the far-field. A 4-fold enhancement of the circular dichroism and a strong optical activity of ∼15 degrees have been experimentally achieved. Besides the enhanced chirality, our design genuinely overcomes...
ACS Nano, 2017
Separating substances by their chirality faces great challenges as well as opportunities in chemi... more Separating substances by their chirality faces great challenges as well as opportunities in chemistry and biology. In this study, we propose an all-optical solution for passive sorting of chiral objects using chirality-dependent lateral optical forces induced by judiciously interfered fields. First, we investigate the optical forces when the chiral objects are situated in the interference field formed by two plane waves with arbitrary polarization states. When the plane waves are either linearly or circularly polarized, nonzero lateral forces are found at the particle's trapping positions, making such sideways motions observable. Although the lateral forces have different magnitudes on particles with different chirality, their directions are the same for opposite handedness particles, rendering it difficult to separate the chiral particles. We further solve the sorting problem by investigating more complicated polarization states. Finally, we achieve the chiral-selective separation by illuminating only one beam toward the chiral substance situated at an interface between two media, taking advantage of the native interference between the incident and reflective beams at the interface. Our study provides a robust and insightful approach to sort chiral substances and biomolecules with plausible optical setups.
Applied Physics Express, 2016
We report a sub-terahertz (THz) detector based on a 0.25-µm-gate-length AlGaN/GaN high-electron-m... more We report a sub-terahertz (THz) detector based on a 0.25-µm-gate-length AlGaN/GaN high-electron-mobility transistor (HEMT) on a Si substrate with nanoantennas. The fabricated device shows excellent performance with a maximum responsivity (R v) of 15 kV/W and a minimal noise equivalent power (NEP) of 0.58 pW/Hz0.5 for 0.14 THz radiation at room temperature. We consider these excellent results as due to the design of asymmetric nanoantennas. From simulation, we show that indeed such nanoantennas can effectively enhance the local electric field induced by sub-THz radiation and thereby improve the detection response. The excellent results indicate that GaN HEMTs with nanoantennas are future competitive detectors for sub-THz and THz imaging applications.
Journal of the Optical Society of America B, 2016
Graphene plasmons have attracted a lot of attention due to large confinement and small mode volum... more Graphene plasmons have attracted a lot of attention due to large confinement and small mode volume. However, the graphene-based plasmonic devices are still limited in the practical applications due to relatively small light absorption of graphene and limited light-matter coupling efficiency in general excitation strategy. Here, this work reported a strong plasmonic coupling effect observed in a novel graphene-Bi 2 Te 3 heterostructure on the top of silicon gratings. It is interesting to find that the extinction spectra of the graphene-Bi 2 Te 3 heterostructure has shown three times greater magnitude than that of graphene. This observation is mainly attributed to two factors: first, the coupling efficiency between the graphene and Bi 2 Te 3 second, the higher light absorption in the graphene-Bi 2 Te 3 heterostructure. Moreover, the plasmonic resonance peak of the graphene-Bi 2 Te 3 heterostructure can be easily tuned by changing the grating period just like what happens in the graphene film. In all, this work utilizes the simple silicon grating to couple the light into the graphene-Bi 2 Te 3 heterostructure, and further explores the hybridized Dirac plasmons in the graphene-Bi 2 Te 3 heterostructure. We believe it will stimulate the interest to study the variant plasmonic heterostructure and trigger new terahertz device applications.
Advanced Optical Materials, 2016
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Journal Publications by Imre.dr. Teng Jing Hua
plates (LSZPs) are proposed to produce as well as focus optical vortices with a long focal depth in the broadband visible range. Topologically breaking the in-plane symmetry, this nanoengineered LSZP continuously modulates both
amplitude and phase in the diffraction field to shape twisted focusing of the optical vortex beam, which is microscopically confined and spatially spiraling with variant crescent-shaped transverse intensity profiles. Owing to its rich structural degree of freedom upon aperiodic and continuously variant features, the LSZP provides a compact solution to generate and control optical vortices carrying scalable OAM and highly concentrated photons with a high transmission efficiency of ∼22%. This can offer new opportunities for 3D light shaping,
Papers by Imre.dr. Teng Jing Hua
plates (LSZPs) are proposed to produce as well as focus optical vortices with a long focal depth in the broadband visible range. Topologically breaking the in-plane symmetry, this nanoengineered LSZP continuously modulates both
amplitude and phase in the diffraction field to shape twisted focusing of the optical vortex beam, which is microscopically confined and spatially spiraling with variant crescent-shaped transverse intensity profiles. Owing to its rich structural degree of freedom upon aperiodic and continuously variant features, the LSZP provides a compact solution to generate and control optical vortices carrying scalable OAM and highly concentrated photons with a high transmission efficiency of ∼22%. This can offer new opportunities for 3D light shaping,