| 1. |
- Gong, Chensheng, et al.
(författare)
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Upconversion enhancement by a dual-resonance all-dielectric metasurface
- 2019
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Ingår i: Nanoscale. - : ROYAL SOC CHEMISTRY. - 2040-3364 .- 2040-3372. ; 11:4, s. 1856-1862
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Tidskriftsartikel (refereegranskat)abstract
- Upconversion nanoparticles (UCNPs) have drawn much attention in the past decade due to their superior physicochemical features and great potential in biomedical and biophotonic studies. However, their low luminescence efficiency often limits their applications. Here, we demonstrated a dual-resonance all-dielectric metasurface to enhance the signals emitted by upconversion nanoparticles (NaYF4:Yb/Tm). An averaged upconversion signal enhancement of around 400 times is detected experimentally. The electric and magnetic dipole resonances of the metasurface are designed to enhance the local excitation field and the quantum efficiency of the upconversion nanoparticles, respectively. Furthermore, the collection efficiency is enhanced due to the directional emission of the UCNPs on the metasurface. Our approach provides a powerful tool to extend the sensing application potential of upconversion nanoparticles.
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| 2. |
- He, Nan, et al.
(författare)
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All-in-One Collimating Splitter Based on a Meta-Fiber Platform
- 2023
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Ingår i: Applied Sciences. - : MDPI AG. - 2076-3417. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- The use of array generators has become ubiquitous in various applications such as laser fabrication, face identification, and motion sensing. The Dammann grating, a diffractive optical element, is the mainstream approach for generating uniform spot arrays. However, its limited capability and the contradiction between the performance and the complexity of fabrication hinder its application. To address this issue, an all-in-one collimating splitter based on metasurfaces is theoretically proposed by synthesizing the phase of an inverse-optimized Dammann grating and a collimating lens. Leveraging both the diffraction effect of Dammann grating and the Fourier transformation of the collimating lens, the number of spot arrays can be largely increased with a single lenslet. The proposed design shows a large field of view of 62 degrees x 62 degrees ffi and a high uniformity of 1.29% in generating a spot array of 3 x 3 on a single-fiber platform, confirmed by both the scalar and full-wave simulation. Further, a larger spot array up to 15 x 15 is also derived in the far field by integrating the proposed metasurface on a 5 x 5 fiber array platform, confirmed by the scalar simulation. Our design may be transplanted to the vertical-cavity surface-emitting laser platform, and shows great potential in various applications including face identification and motion sensing.
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| 3. |
- He, Nan, et al.
(författare)
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High-Speed Duplex Free Space Optical Communication System Assisted by a Wide-Field-of-View Metalens
- 2023
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Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 10:9, s. 3052-3059
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Tidskriftsartikel (refereegranskat)abstract
- Free space optical communication (FSO) has gained significant attention due to the growing demand for a high information capacity. For FSO between multiple or moving targets, a receiver with a wide angle of acquisition capability is necessary. Traditionally, gimbals and fast steering mirrors have been used, but they are often difficult to make both compact and wide-angle. Here, a novel duplex FSO system is demonstrated, which utilizes a highly compact fiber coupling metalens to receive and transmit signals in a large field of view up to 80°. High coupling efficiency up to 48.8% at a wavelength of 1550 nm is experimentally achieved. The small coupling loss enables the user to modulate and direct the downstream power from the base station back along the same path, saving energy and leaving only one source in the FSO system. The low bit error rate and the open and clear eye diagram results validate the excellent downlink/uplink communication performance of a 10 Gbps FSO system empowered by the metalens. The system exhibits a large field of view, high data rate, compact size, and low power consumption, which meets the size, weight, and power requirement of smart devices.
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| 4. |
- Hu, Zhipeng, et al.
(författare)
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Wideband High-Reflection Chiral Dielectric Metasurface
- 2021
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Ingår i: Progress In Electromagnetics Research. - : EMW PUBLISHING. - 1070-4698 .- 1559-8985. ; 172, s. 51-60
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Tidskriftsartikel (refereegranskat)abstract
- Compared to natural materials, artificial subwavelength structures can enhance chiroptical effects in a stronger way, and the requirement of low material loss and wideband operation is desired in many situations. Here, we propose an all-dielectric chiral metasurface as a periodic array of centrosymmetric staggered silicon cuboid pairs to achieve strong circular dichroism in a wide band. As a demonstration, the designed chiral metasurface may strongly reflect the chosen circularly polarized light with the spin preserved in the operating wavelength range of 1.51 ti 1.60 mu m while highly transmit (with an efficiency greater than 95%) the opposite circularly polarized light with the spin flipped. Then, two application cases are given for the designed chiral metasurface. A flat chiral meta-lens is constructed to produce wideband focusing in the transmission/reflection side while the disturbing from the opposite circular polarization is well blocked by high reflection/transmission. A chiral Fabry-Perot cavity is also constructed, which has an extremely high quality factor (2.1E4). The proposed method provides an efficient way to produce strong chiroptical effects and has a promising potential for various applications such as signal processing, sensing, radiation and detection.
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| 5. |
- Li, Junhao, et al.
(författare)
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Full-color enhanced second harmonic generation using rainbow trapping in ultrathin hyperbolic metamaterials
- 2021
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Though metamaterials enhance nonlinear light-matter interactions due to their resonant features, these materials typically show a narrow spectral bandwidth. Here, the authors report broadband enhanced second-harmonic generation in patterned multilayer hyperbolic metamaterial arrays. Metasurfaces have provided a promising approach to enhance the nonlinearity at subwavelength scale, but usually suffer from a narrow bandwidth as imposed by sharp resonant features. Here, we counterintuitively report a broadband, enhanced second-harmonic generation, in nanopatterned hyperbolic metamaterials. The nanopatterning allows the direct access of the mode with large momentum, rendering the rainbow light trapping, i.e. slow light in a broad frequency, and thus enhancing the local field intensity for boosted nonlinear light-matter interactions. For a proof-of-concept demonstration, we fabricated a nanostructured Au/ZnO multilayer, and enhanced second harmonic generation can be observed within the visible wavelength range (400-650 nm). The enhancement factor is over 50 within the wavelength range of 470-650 nm, and a maximum conversion efficiency of 1.13x10(-6) is obtained with a pump power of only 8.80 mW. Our results herein offer an effective and robust approach towards the broadband metasurface-based nonlinear devices for various important technologies.
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| 6. |
- Sampson, Joshua N., et al.
(författare)
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Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
- 2015
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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| 7. |
- Shi, Kezhang, et al.
(författare)
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Colossal Enhancement of Near-Field Thermal Radiation Across Hundreds of Nanometers between Millimeter-Scale Plates through Surface Plasmon and Phonon Polaritons Coupling
- 2019
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 19:11, s. 8082-8088
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Tidskriftsartikel (refereegranskat)abstract
- Coupling modes between surface plasmon polaritons (SPPs) and surface phonon polaritons (SPhPs) play a vital role in enhancing near-field thermal radiation but are relatively unexplored, and no experimental result is available. Here, we consider the NFTR enhancement between two identical graphene-covered SiO2 heterostructures with millimeter-scale surface area and report an experimentally record-breaking, similar to 64-fold enhancement compared to blackbody (BB) limit at a gap distance of 170 nm. The energy transmission coefficient and radiation spectra show that the physical mechanism behind the colossal enhancement is the coupling between the surface plasmon and phonon polaritons.
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| 8. |
- Tian, Jiahan, et al.
(författare)
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Wide-field-of-view auto-coupling optical antenna system for high-speed bidirectional optical wireless communications in C band
- 2023
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 31:20, s. 33435-33448
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Tidskriftsartikel (refereegranskat)abstract
- Due to a great many superior features of infrared light communication (ILC), like high capacity and strong privacy, ILC is considered a potential candidate for serving the high demands of beyond fifth-generation/sixth-generation (B5G/6 G) communication systems. However, the terminal's limited field-of-view (FOV) induces great difficulty in establishing line-of-sight (LoS) link between the transceiver and the terminal. In this paper, we propose a wide-FOV auto-coupling optical antenna system that utilizes a wide-FOV telecentric lens to collect incident infrared beams and automatically couple them into a specific single-mode-fiber (SMF) channel of fiber array and optical switch. The performance of this optical antenna system is assessed through simulation and manual alignment operation, and validated by automatic alignment results. A coupling loss of less than 10.6 dB within a FOV of 100(degrees )for both downstream and upstream beams in C band is demonstrated by the designed system. Furthermore, we establish a bidirectional optical wireless communications (OWC) system employing this antenna and a fiber-type modulating retro-reflector (MRR) system in the terminal. Both 10-Gbps on-off keying (OOK) downstream and upstream transmissions are successfully realized with the FOV of up to 100(degrees) in C band where the measured bit-error-rate (BER) is lower than 3.8 x 10-3. To the best of our knowledge, this is a brand-new auto-coupling optical antenna system with the largest FOV in ILC automatic alignment works in terminals that have ever been reported.
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| 9. |
- Tian, Jiahan, et al.
(författare)
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Wide-Field-of-View Modulating Retro-Reflector System Based on a Telecentric Lens for High-Speed Free-Space Optical Communication
- 2023
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Ingår i: IEEE Photonics Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1943-0655. ; 15:5
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Tidskriftsartikel (refereegranskat)abstract
- Modulating retro-reflector (MRR) free-space optical (FSO) communication technology presents a bright future for realizing the small size, weight, and power (SWaP) design of one end of the optical link, facilitating the further application of the FSO communication to the small platforms. However, the limited field-of-view (FOV) of MRR impedes its wide employment. In this article, a novel wide-FOV MRR using an image space telecentric lens is proposed and a bidirectional FSO communication system is experimentally demonstrated using this MRR with a single light source. The performance of the telecentric lens between the transceiver and terminal is assessed by simulation and also validated by experimental results, with a coupling loss less than 9.1 dB within a FOV of 110 degrees. Both 10-Gbit/s on-off keying (OOK) downstream and upstream signals for free space communication at different incident angles are successfully realized using this designed wide-FOV MRR. The experimental results validate the proposed MRR has a FOV of up to 110 degrees where the measured bit error rate (BER) is lower than 3.8 x 10-3 for both downstream and upstream signals. To the best of our knowledge, this is the largest FOV ever reported for MRRs in high-speed bidirectional FSO communication systems.
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| 10. |
- Wang, Yang, et al.
(författare)
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Benchmarking OpenMP Programs for Real-Time Scheduling
- 2017
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Ingår i: 2017 IEEE 23Rd International Conference On Embedded And Real-Time Computing Systems And Applications (RTSCA). - : IEEE Computer Society. - 9781538618981
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Konferensbidrag (refereegranskat)abstract
- Real-time systems are shifting from single-core to multi-core processors. Software must be parallelized to fully utilize the computation power of multi-core architecture. OpenMP is a popular parallel programming framework in general and high-performance computing, and recently has drawn a lot of interests in embedded and real-time computing. Much recent work has been done on real-time scheduling of OpenMP-based parallel workload. However, these studies conduct evaluations with randomly generated task systems, which cannot well represent the structure features of OpenMP workload. This paper presents a benchmark suite, ompTGB, to support research on real-time scheduling of OpenMP-based parallel tasks. ompTGB does not only collect realistic OpenMP programs, but also models them into task graphs so that the real-time scheduling researchers can easily understand and use them. We also present a new response time bound for a subset of OpenMP programs and use it to demonstrate the usage of ompTGB.
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