Publications

 

 

1、On-Chip Near-Infrared Spectral Sensing with Minimal Plasmon-Modulated Channels

Qilin Zheng, Xianghong Nan, Bojun Chen, Haiquan Wang, Hu Nie, Mengting Gao, Zhong Liu, Long Wen,* David R.S. Cumming, and Qin Chen*.On-Chip Near-Infrared Spectral Sensing with Minimal Plasmon-Modulated Channels.Laser & Photonics Reviews

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2、High-efficienct narrow-band plasmonic hot electron conversion from nanoscale sodium-silicon heterost

Long Wen, Jiaxiang Li, Yajin Dong, Zaizhu Lou, Qin Chen* .  High-efficiency narrow-band plasmonic hot electron conversion from nanoscale sodium-silicon heterostructures.Journal of Applied Physics

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3、On-chip readout plasmonic mid-IR gas sensor

Qin Chen*, Li Liang, Qilin Zheng, Yaxin Zhang, Long Wen*. On-chip readout plasmonic mid-IR gas sensor Opto-Electronic Advances

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4、Ultra-broadband spatial light modulation with dual-resonance coupled epsilon-near-zero materials

Qin Chen*, Shichao Song, Huacun Wang, Li Liang, Yajin Dong, Long Wen* . Ultra-broadband spatial light modulation with dual-resonance coupled epsilon-near-zero materials Nano Research

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5、Miniaturized Spectroscopy with Tunable and Sensitive Plasmonic Structures

Li Liang#, Qilin Zheng#, Long Wen, David R. S. Cumming, Qin Chen* . Miniaturized Spectroscopy with Tunable and Sensitive Plasmonic Structures Optics Letters

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6、Quick response code like full-color nanorouters for high resolution image sensors

Mingjie Chen#, Long Wen#, Dahui Pan, David R. S. Cumming, Xianguang Yang*, Qin Chen*. Quick response code like full-color nanorouters for high resolution image sensors Nanoscale

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7、Nanophotonic Color Routing

Qin Chen*, Xianghong Nan, Mingjie Chen, Dahui Pan, Xianguang Yang, Long Wen* . Nanophotonic Color Routing Advanced Materials

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8、Broad-band spatial light modulation with dual Epsilon-near-zero modes

Long Wen#, Xianghong Nan#, Jiaxiang Li, David R. S. Cumming*, Xin Hu*, Qin Chen* . Broad-band spatial light modulation with dual Epsilon-near-zero modes Opto-Electronic Advances

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9、Plasmonic near-infrared photoconductor based on hot hole collection in the metal-semiconductor-metal

Zhiwei Sun#, Yongsheng Zhong#, Yajin Dong, Qilin Zheng, Xianghong Nan, Zhong Liu, Long Wen*, Qin Chen*, Plasmonic near-infrared photoconductor based on hot hole collection in the metal-semiconductor-metal junction, Molecules

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10、CMOS Compatible Broadband Hot Carrier Photodetection with Cu-Silicon Nanojunctions

Yajin Dong#, Jiaxiang Li#, Wenyue Liang, Xianghong Nan, Long Wen*, Qin Chen*. CMOS Compatible Broadband Hot Carrier Photodetection with Cu-Silicon Nanojunctions ACS Photonics

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11、On-Chip Ultrasensitive and Rapid Hydrogen Sensing based on Plasmon-Induced Hot Electron-Molecule

  L. Wen, Z. Sun, Q. Zheng, X. Nan, Z. Lou, Z. Liu, D. R. S. Cumming, B. Li and Q. Chen*. On-Chip Ultrasensitive and Rapid Hydrogen Sensing based on Plasmon-Induced Hot Electron-Molecule Interaction Light:Science & Applications

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12、CMOS-Compatible Broad-Band Hot Carrier Photodetection with Cu–Silicon Nanojunctions

Yajin Dong, Jiaxiang Li, Wenyue Liang, Xianghong Nan, Long Wen, Qin Chen.ACS Photonics.2022/11/2

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Plasmonic harvesting of hot carriers (HCs) in metal–semiconductor (M–S) junctions has stimulated intensive research activities for sub-bandgap photodetection, in particular the development of silicon-based infrared photodetectors. Here, a copper–silicon heterojunction was investigated both theoretically and experimentally in comparison to the commonly used gold–silicon ones. A 1-order-of-magnitude higher responsivity and a longer cutoff wavelength over 2000 nm were observed in experiments in the sub-bandgap wavelength range of silicon with a copper–silicon junction. A phenomenological model was developed to analyze the dynamic processes of HCs and attributed the advanced photodetection performance of copper–silicon devices to the relatively higher electron density of state above the Fermi level and the higher ejection probability. Such a complementary metal–oxide–semiconductor-compatible …

13、Reversible Active Switching of Fano and Fabry–Pérot Resonances by Electrochromic Operation

Jian Chen, Yaowu Li, Taoyang Zhang, Xiuling Zha, Xueqing Tang, Xinyang Mu, Peiyan Sun, Ge Song, Shan Cong, Qin Chen, Zhigang Zhao.Laser & Photonics Reviews.2022/10

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Resonances are ubiquitous in modern photonics, with the more familiar Fano and Fabry–Pérot resonators as key components of sophisticated optical devices with unique properties. However, the fundamental drawback of these devices is the difficulty in altering the resonance‐related features of the underlying optical structures postfabrication. This study investigates an active electrochromic tungsten oxide (WO3)‐based reconfigurable photonic structure with reversible switching between the Fano and Fabry–Pérot (F–P) resonances. This remarkable resonance switching occurs as a result of a change in the WO3 film optical indices (n, k) via Li+ intercalation/deintercalation, which can be inferred from the spectral response or dynamic reflected colors. When the bottom Ag layer's thickness is decreased from 130 to 10 nm, a semitransparent structure with unique optical properties emerges. The F–P resonant structure …

14、Research progress of on-chip integrated optical sensing technology (Invited)

Chen Qin, Nan Xianghong, Liang Wenyue, Zheng Qilin, Sun Zhiwei, Wen Long.红外与激光工程.2022/1/25

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Optical sensing technology has been widely used because of its advantages of high precision, low delay and imaging. With the rapid development of information technology such as big data and Internet of things, the demand for miniaturization and portability of optical detection and inspection platform is becoming more and more urgent. In order to overcome the dependence on large-scale special equipment and improve the applicability of on-site rapid detection and light-load platform application scenarios, in recent years on-chip integrated optical sensing technology has attracted great attention. With the integration of optical source, optical sensing and photoelectric detection units, as well as the development of on-chip light dispersion technology, the on-chip integration of optical sensing signal extraction and photoelectric signal conversion can be effectively realized, which contributes to the realization of the …

15、Energy dissipation and asymmetric excitation in hybrid waveguides for routing and coloring

Xianguang Yang, Long Wen, Jiahao Yan, Yanjun Bao, Qin Chen, Andrea Camposeo, Dario Pisignano, Baojun Li.The Journal of Physical Chemistry Letters.2021/7

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The delivery of optical signals from an external light source to a nanoscale waveguide is highly important for the development of nanophotonic circuits. However, the efficient coupling of external light energy into nanophotonic components is difficult and still remains a challenge. Herein, we use an external silica nanofiber to light up an organic–inorganic hybrid nanowaveguide, namely, a system composed of a polymer filament doped with MoS2 quantum dots. Nanofiber-excited nanowaveguides in a crossed geometry are found to asymmetrically couple excitation signals along two opposite directions, with different energy dissipation resulting in different colors of the light emitted by MoS2 quantum dots and collected from the waveguide terminals. Interestingly, rainbow-like light in the hybrid waveguide is achieved by three-in-one mixing of red, green, and blue components. This heterodimensional system of dots in …

16、Full View Full-color nanorouter for high-resolution imaging

Mingjie Chen, Long Wen, Pan Dahui, David R. S. Cumming, Xianguang Yang, Qin Chen.Nanoscale.2021/7

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Pixel scaling effects have been a major issue in the development of high-resolution color image sensors due to the reduced photoelectric signal and color crosstalk. Various structural color techniques have been proposed, and the large freedom in color manipulation by the structure design has been demonstrated. However, the optical efficiency and color distortion limit the practical applications due to their intrinsic filtering mechanism. Instead, the on-chip full-color routing is quite desirable for improving the signal-to-noise ratio. In this study, a single-layer quick response code-like nanorouter is proposed for the full-color light routing in a pixel level of image sensors. It shows much higher routing efficiency than various planar lens schemes for signal wavelength focusing. Moreover, over 60% signal enhancement with robust polarization insensitivity is obtained in all three primary color bands with the same nanorouter …

17、Toward the capacity limit of 2D planar Jones matrix with a single-layer metasurface

Yanjun Bao, Long Wen, Qin Chen, Cheng-Wei Qiu, Li Baojun.Science Advances.2021/6

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The Jones matrix is a useful tool to deal with polarization problems, and its number of degrees of freedom (DOFs) that can be manipulated represents its polarization-controlled capabilities. A metasurface is a planar structure that can control light in a desired manner, which, however, has a limited number of controlled DOFs (≤4) in the Jones matrix. Here, we propose a metasurface design strategy to construct a Jones matrix with six DOFs, approaching the upper-limit number of a 2D planar structure. We experimentally demonstrate several polarization functionalities that can only be achieved with high (five or six) DOFs of the Jones matrix, such as polarization elements with independent amplitude and phase tuning along its fast and slow axes, triple-channel complex-amplitude holography, and triple sets of printing-hologram integrations. Our work provides a platform to design arbitrary complex polarization elements …

18、Mimicking Nature's Butterflies: Electrochromic Devices with Dual‐Sided Differential Colorations

Jian Chen, Zhen Wang, Chenglong Liu, Zhigang Chen, Xueqing Tang, Qi Wu, Shu Zhang, Ge Song, Shan Cong, Qin Chen, Zhigang Zhao.Advanced Materials.2021/4

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Some butterfly species such as the orange oakleaf (Kallima inachus) have strikingly different colors on the dorsal (front) sides of their wings compared to those on the ventral (back) sides of their wings, which helps camouflage the butterflies from predators and attract potential mates. However, few human‐made materials, devices, and technologies can mimic such differential coloring for a long time. Here, a new type of Janus‐structured two‐sided electrochromic device is developed that, upon application of different voltages, exhibits a coloration state on one side that is distinctly different from that on the other side. This is achieved by inserting an optically thin (4–8 nm) metallic layer with a complex refractive index, such as a layer composed of tungsten, titanium, copper or silver, into typical electrochromic structures.

19、Hybrid Optoelectronic Materials for Photodetection Applications

Xianguang Yang, Qin Chen, Baojun Li.Advances in Optoelectronic Materials.2021

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One-dimensionalOne-dimensional-hybrid optoelectronic materials hybrid optoelectronic materialsHybrid-optoelectronic materials based photodetectors are highly desirable because low-dimensional nanostructuresNanostructure are fascinating platforms for manipulating electrons and photons at the sub-wavelengthWavelength scale. In this chapter, we reported two types of ultraviolet–visible photodetectorsUltraviolet–visible-photodetectors based on a singleSingle-hybrid nanowire hybrid nanowireHybrid-nanowire and a crossedJunctionjunctionCrossed junction formed with two-hybrid nanowiresHybrid-nanowire, respectively. For a single nanowireNanowires device, the high-performancePerformance is attributed to the high density of trapping statesTrapping-states at the organic-inorganicInorganicinterfacesInterface. For crossed junctionCrossed junction device, the excellent performancePerformance is mainly …

20、Research progress of computational microspectrometer based on speckle inspection [J]

QL Zheng, L Wen, Q Chen.Opto-Electronic Engineering.2021

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Fast, accurate and nondestructive spectral analysis technique is important and widely used in the fields of scientific research, information, biomedical, pharmaceutical detection, agriculture, environment, and security. However, the existing spectroscopic analysis equipments are usually bulky and complex, which are difficult to adapt to portable application scenarios such as on-site rapid detection, light-load platform, etc. In recent years, miniature spectroscopic detection technology and equipment have received extensive attention, and have been rapidly developed, with significant advantages in size, weight, and power consumption. In particular, the computational spectral analysis technology based on the speckle detection can obtain high-precision spectral information by recording and analyzing the speckle pattern formed by the scattering element on the measured light. This paper will first introduce the related …

21、High-efficiency narrow-band plasmonic hot electron conversion from nanoscale sodium–silicon heterost

Long Wen, Jiaxiang Li, Yajin Dong, Zaizhu Lou, Qin Chen.Journal of Applied Physics.2020/12

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Plasmonic harvesting of hot electrons has stimulated intensive research activities for applications ranging from sub-bandgap photodetection to photocatalysis. Both high photoelectric conversion efficiency and tunable spectral response are pursued by manipulating resonant metal–semiconductor (M–S) nanostructures. Although noble plasmonic metals have been exclusively employed in hot electron conversion studies, exploring new materials may offer an additional degree of freedom to manipulate the hot electron generation, transport, and emission processes. In this paper, we propose to employ the low-loss alkali metal sodium as an alternate plasmonic material for developing a narrow-band resonant hot electron device. Based on a backside-illumination (BSI) configuration where plasmonic hot electrons generate locally at the M–S interface, the transport loss can be significantly suppressed. Thanks to its …

22、表面等离激元增强硅基近红外光电导探测器

唐恝， 李家祥， 陈沁， 文龙.中国激光.2020/10

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近年来, 表面等离激元 (SP) 增强的金属纳米结构中热载流子产生, 传输和收集得到了广泛而深入的研究. 其中, 利用电子隧穿和热发射效应实现的全新光电转换机制, 结合平面化制作和 CMOS 兼容集成等, 有望成为硅基红外光电探测的备选方案. 目前这类探测器主要为金属-半导体肖特基结的光伏型器件, 其光电响应较弱. 为此, 报道了一种基于金属-硅复合无序纳米结构的光电导器件, 得益于无序表面等离激元局域热点效应和多叉指金属-半导体-金属 (MSM) 结构的显著光电导增益, 实验获得了硅亚带隙的宽带强光电响应. 该热载流子介导的多叉指 MSM 器件在 1310nm 波长处的光电流响应度高达 2.50 A/W.

23、Infrared Nanoimaging of Surface Plasmons in Type-II Dirac Semimetal PtTe2 Nanoribbons

Xin Hu, Kin Ping Wong, Longhui Zeng, Xuyun Guo, Tong Liu, Lei Zhang, Qin Chen, Xuefeng Zhang, Ye Zhu, Kin Hung Fung, Shu Ping Lau.ACS nano.2020/5

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Topological Dirac semimetals made of two-dimensional transition-metal dichalcogenides (TMDCs) have attracted enormous interest for use in electronic and optoelectronic devices because of their electron transport properties. As van der Waals materials with a strong interlayer interaction, these semimetals are expected to support layer-dependent plasmonic polaritons yet to be revealed experimentally. Here, we demonstrate the apparent retardation and attenuation of mid-infrared (MIR) plasmonic waves in type-II Dirac semimetal platinum tellurium (PtTe2) nanoribbons and nanoflakes by near-field nanoimaging. The attenuated dispersion relations for the plasmonic modes in the PtTe2 nanoribbons (15–25 nm thick) extracted from the near-field standing-wave patterns are applied for the fitting of PtTe2 permittivity in the MIR regime, indicating that both free carriers and Dirac fermions are involved in MIR light–matter …

24、Multispectral imaging via nanostructured random broadband filtering

Xiaolin Wu, Dahua Gao, Qin Chen, Jie Chen.Optics Express.2020/2

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It is a challenge to acquire a snapshot image of very high resolutions in both spectral and spatial domain via a single short exposure. In this setting one cannot trade time for spectral resolution, such as via spectral bands scanning. Cameras of color filter arrays (CFA) (e.g., the Bayer mosaic) cannot obtain high spectral resolution. To overcome these difficulties, we propose a new multispectral imaging system that makes random linear broadband measurements of the spectrum via a nanostructured multispectral filter array (MSFA). These MSFA random measurements can be used by sparsity-based recovery algorithms to achieve much higher spectral resolution than conventional CFA cameras, without sacrificing spatial resolution. The key innovation is to jointly exploit both spatial and spectral sparsity properties that are inherent to spectral irradiance of natural objects. Experimental results establish the superior …

25、Towards full-colour tunability of inorganic electrochromic devices using ultracompact fabry-perot na

Zhen Wang, Xiaoyu Wang, Shan Cong, Jian Chen, Hongzhao Sun, Zhigang Chen, Ge Song, Fengxia Geng, Qin Chen, Zhigang Zhao.Nature communications.2020/1

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Intercalation-based inorganic materials that change their colours upon ion insertion/extraction lay an important foundation for existing electrochromic technology. However, using only such inorganic electrochromic materials, it is very difficult to achieve the utmost goal of full-colour tunability for future electrochromic technology mainly due to the absence of structural flexibility. Herein, we demonstrate an ultracompact asymmetric Fabry-Perot (F-P) nanocavity-type electrochromic device formed by using partially reflective metal tungsten as the current collector and reflector layer simultaneously; this approach enables fairly close matching of the reflections at both interfaces of the WO3 thin layer in device form, inducing a strong interference. Such an interference-enhanced device that is optically manipulated at the nanoscale displays various structural colours before coloration and, further, can change to other colours …

26、Multiband and ultrahigh figure-of-merit nanoplasmonic sensing with direct electrical readout in Au-S

Long Wen, Li Liang, Xianguang Yang, Zhong Liu, Baojun Li, Qin Chen.ACS nano.2019/6

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Nanoplasmonic sensors are heralding exciting advances as clinical diagnostics as they facilitate label-free, real-time, and ultrasensitive monitoring in a small footprint. But in essence, almost all of them still largely rely on expensive and bulky spectroscopy/imaging instrumentation and methodology, which has become the major impediment for point-of-care (POC) testing implantation. In this context, an ultracompact optical sensor is achieved with direct electrical read-out capacity by combining plasmonic sensing resonance and optical-signal-transducing into a unity integrated device. Benefiting from the convergence of high figure-of-merit (∼190) resonance and hot electron enhanced photoelectric conversions on the near-flat Au-Si nanotrench framework, the device is demonstrated to yield a detection limit on the order of 10–6 RIU in a broadband operating wavelength window (700–1700 nm). Such a compact …

27、Research progress of terahertz sensor based on artificial microstructure

Liang Li, Wen Long, Jiang Chunping, Chen Qin.红外与激光工程.2019/2/25

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Recently, terahertz (THz) technology has developed rapidly, showing promising potential in the fields of communication, anti-terrorism, monitoring and biomedicine, etc. In particular, terahertz biosensor has attracted extensive attentions in biotechnology, because many biological molecules and materials have their finger prints in the THz absorption spectra, and the damage by the low power terahertz wave is low. However, the THz wave-matter interaction is relatively weak because of the mismatch between the long wavelength of THz wave and the size of biomolecules, which limits the performance of terahertz sensors. Current research interest is manipulating the spatial and spectral distributions of the electromagnetic fields based on the microstructures to enhance the sensitivity of the sensors. In this review, we are going to introduce the working mechanisms of various microstructure THz sensors and the recent …

28、Large phase modulation of THz wave via an enhanced resonant active HEMT metasurface

Yaxin Zhang, Yuncheng Zhao, Shixiong Liang, Bo Zhang, Lan Wang, Tianchi Zhou, Wei Kou, Feng Lan, Hongxin Zeng, Jiaguang Han, Zhihong Feng, Qin Chen, Pinaki Mazumder, Ziqiang Yang.Nanophotonics.2019/1

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Terahertz (THz) science and technology promise unique applications in high-speed communications, high-accuracy imaging, and so on. To keep up with the demand for THz systems, THz dynamic devices should feature large phase shift modulation and high speed. To date, however, only a few devices can efficiently manipulate the phase of THz waves. In this paper, we demonstrate that efficient phase modulation of THz waves can be addressed by an active and enhanced resonant metamaterial embedded with a nanostructured 2D electron gas (2DEG) layer of a GaN high electron mobility transistor (HEMT). The enhanced resonant metaunit couples the traditional dipolar and inductance-capacitance resonances together to realize a coupling mode with enhanced resonance. Embedded with the nanostructured 2DEG layer of GaN HEMT, the resonance intensity and surface current circuit of the enhanced resonant …

29、Polarization-insensitive surface plasmon polarization electro-absorption modulator based on epsilon-

Lin Jin, Long Wen, Li Liang, Qin Chen, Yunfei Sun.Nanoscale research letters.Nanoscale research letters.2018/12

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CMOS-compatible plasmonic modulators operating at the telecom wavelength are significant for a variety of on-chip applications. Relying on the manipulation of the transverse magnetic (TM) mode excited on the metal-dielectric interface, most of the previous demonstrations are designed to response only for specific polarization state. In this case, it will lead to a high polarization dependent loss, when the polarization-sensitive modulator integrates to a fiber with random polarization state. Herein, we propose a plasmonic modulator utilizing a metal-oxide indium tin oxide (ITO) wrapped around the silicon waveguide and investigate its optical modulation ability for both the vertical and horizontal polarized guiding light by tuning electro-absorption of ITO with the field-induced carrier injection. The electrically biased modulator with electron accumulated at the ITO/oxide interface allows for epsilon-near-zero (ENZ …

30、Unity Integration of Grating Slot Waveguide and Microfluid for Terahertz Sensing

Li Liang, Xin Hu, Long Wen, Yuhuan Zhu, Xianguang Yang, Jun Zhou, Yaxin Zhang, Ivonne Escorcia Carranza, James Grant, Chunping Jiang, David RS Cumming, Baojun Li, Qin Chen.Laser & Photonics Reviews.2018/11

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Refractive index sensing is attracting extensive interest. Limited by the weak light–matter interaction and the broad bandwidth of resonance, the figure of merit (FoM) of terahertz (THz) sensors is much lower than their counterparts in visible and infrared regions. Here, these two issues are addressed by incorporating a microfluidic channel as a slot layer into a grating slot waveguide (GSW), where guided‐mode resonance results in a narrowband resonant peak and the sensitivity increases remarkably due to the greatly concentrated electromagnetic fields in the slot layer. Both reflective and transmissive sensors are developed with the calculated quality (Q) factors two orders of magnitude larger than metamaterial and plasmonic sensors, and the sensitivities one order of magnitude larger than grating waveguide sensors, contributing to a record high FoM of 692. The measured results match well with the simulations …

31、Discrete optical field manipulation by Ag-Al bilayer gratings for broadband absorption enhancement i

Yifu Chen, Long Wen, Xin Hu, Run Xu, Qin Chen.Plasmonics.2018/10

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Plasmonic gratings have been widely used for light harvesting in thin-film solar cells (TFSCs). However, the detrimental parasitic metal absorption loss limits the actual light absorption in the active layer and reduces the power conversion efficiency. In this paper, it is found that the localized surface plasmon resonance (LSPR) used to increase long-wavelength light absorption has significant field concentration around the bottom corners of metal gratings, but the field distribution for the short-wavelength absorption band localizes around the top corners of gratings. Due to the differences between the spatial field distributions and the related mechanisms of metal loss, discrete optical field manipulation is proposed to suppress the ohmic loss mainly associated with LSPR and the interband transition loss associated with metal materials by using Ag-Al bilayer gratings, where Ag has a small absorption coefficient …

32、Optical energy transfer from photonic nanowire to plasmonic nanowire

Xianguang Yang, Yuchao Li, Zaizhu Lou, Qin Chen, Baojun Li.ACS Applied Energy Materials.2018/2

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Rational and versatile transfer of optical energy from photonic nanowire to plasmonic nanowire is highly desirable and extremely challengeable. Herein, we demonstrate that optical energy transfer from CdSe–ZnS core–shell quantum dots doped polymer photonic nanowire to silver plasmonic nanowire with an efficiency of 32 ± 1.5% via the Förster resonance energy transfer process. The quantum dots with an emission at 650 nm wavelength were embedded in polymer nanowire and were excited by a 532 nm green laser. In the crossing region of the photonic nanowire and plasmonic nanowire, propagated surface plasmons of silver nanowire can be effectively excited by the emitted light from quantum dots embedded in polymer nanowire. This energy transfer between photonic and plasmonic nanowires would provide potential applications in optical interconnection.

33、Hot electron harvesting via photoelectric ejection and photothermal heat relaxation in hotspots-enri

Long Wen, Yifu Chen, Li Liang, Qin Chen.ACS Photonics.2018/2

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The ability of plasmonic nanostructures to harvest photons beyond the traditional band-to-band photovoltaic conversion of semiconductors has stimulated intensive research activities in hot electron. As an emerging strategy for energy-harvesting, photodetection and photocatalysis, realization of broadband and efficient plasmonic absorption with easily constructed metal-semconductor (M-S) nanosystems is essential for improving its photoelectric efficiency, while minimizing the cost and complexity of fabrication. Here, we report an approach for near-infrared (NIR) photodetection by combining the randomly and densely packed photonic nanostructures with ultrathin plasmonic coatings. Relying on the Au covered disordered silicon nanoholes (SiNHs) M-S platform, the efficient plasmonic absorption, strong field localization and together with random nature facilitate the broadband photon-energy conversion from both …

34、Enhanced Photoelectric and Photothermal Responses on Silicon Platform by Plasmonic Absorber and Omni

Long Wen, Yifu Chen, Wanwan Liu, Qiang Su, James Grant, Zhiyang Qi, Qilong Wang, Qin Chen.Laser & Photonics Reviews.2017/9

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Recent progresses in plasmon‐induced hot electrons open up the possibility to achieve photon harvesting beyond the fundamental limit imposed by band‐to‐band transitions in semiconductors. To obtain high efficiency, both the optical absorption and electron emission/collection are crucial factors that need to be addressed in the design of hot electron devices. Here, we demonstrate a photoresponse as high as 3.3mA/W at 1500nm on a silicon platform by plasmonic absorber (PA) and omni‐Schottky junction integrated photodetector, reverse biased at 5V and illuminated with 10mW. The PA fabricated on silicon consists of a monolayer of random Au nanoparticles (NPs), a wide‐band gap semiconductor (TiO2) and an optically thick Au electrode, resulting in broadband near‐infrared (NIR) absorption and efficient hot‐electron transfer via an all‐around Schottky emission path. Meanwhile, time and spectral‐resolved …

35、Au nanoparticle-decorated silicon pyramids for plasmon-enhanced hot electron near-infrared photodete

Zhiyang Qi, Yusheng Zhai, Long Wen, Qilong Wang, Qin Chen, Sami Iqbal, Guangdian Chen, Ji Xu, Yan Tu.Nanotechnology.2017/6.

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The heterojunction between metal and silicon (Si) is an attractive route to extend the response of Si-based photodiodes into the near-infrared (NIR) region, so-called Schottky barrier diodes. Photons absorbed into a metallic nanostructure excite the surface plasmon resonances (SPRs), which can be damped non-radiatively through the creation of hot electrons. Unfortunately, the quantum efficiency of hot electron detectors remains low due to low optical absorption and poor electron injection efficiency. In this study, we propose an efficient and low-cost plasmonic hot electron NIR photodetector based on a Au nanoparticle (Au NP)-decorated Si pyramid Schottky junction. The large-area and lithography-free photodetector is realized by using an anisotropic chemical wet etching and rapid thermal annealing (RTA) of a thin Au film. We experimentally demonstrate that these hot electron detectors have broad …

36、Mode properties in metallic and non-metallic plasmonic waveguides

Wanwan Liu, Yifu Chen, Xin Hu, Long Wen, Lin Jin, Qiang Su, Qin Chen.Applied optics.2017/6

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Non-metallic plasmonic materials have recently attracted research interest due to their adjustable plasmonic material properties and the potential low loss, which is important to plasmonic waveguides with ultrahigh mode confinement. In this paper, we analyzed the mode properties of four types of plasmonic waveguides based on noble metals, aluminum-zinc-oxide (AZO), and TiN, where the propagation length and mode size are chosen to compare the figures of merit. It is found that AZO has the smallest imaginary part of permittivity in the near-infrared region, while AZO waveguides have propagation lengths comparable to those of Cu waveguides but shorter than those of Au and Ag waveguides. Furthermore, due to the larger real part of permittivities, the mode sizes of the AZO and TiN waveguides are smaller than those of the metal waveguides, in particular, for the insulator–metal–insulator waveguide and …

37、Multifunctional silicon optoelectronics integrated with plasmonic scattering color

Long Wen, Qin Chen, Xin Hu, Huacun Wang, Lin Jin, Qiang Su.ACS nano.2016/12

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Plasmonic scattering from metallic nanoparticles has been used for centuries to create the colorful appearance of stained glass. Besides their use as passive spectral filtering components, multifunctional optoelectronic applications can be achieved by integrating the nanoscatters with semiconductors that generate electricity using the complementary spectral components of plasmonic colors. To suppress the usual degradation of both efficiency and the gamut of plasmonic scattering coloration in highly asymmetric index configurations like a silicon host, aluminum nanodisks on indium tin oxide (ITO) coated silicon were experimentally studied and demonstrated color sorting in the full visible range along with photocurrent generation. Interestingly, the photocurrents were found to be comparable to the reference devices with only antireflection coatings in spite of the power loss for coloration. Detailed investigation shows …

38、Metamaterial absorber integrated microfluidic terahertz sensors

Xin Hu, Gaiqi Xu, Long Wen, Huacun Wang, Yuncheng Zhao, Yaxin Zhang, David RS Cumming, Qin Chen.Laser & Photonics Reviews.2016/11.

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Spatial overlap between the electromagnetic fields and the analytes is a key factor for strong light‐matter interaction leading to high sensitivity for label‐free refractive index sensing. Usually, the overlap and therefore the sensitivity are limited by either the localized near field of plasmonic antennas or the decayed resonant mode outside the cavity applied to monitor the refractive index variation. In this paper, by constructing a metal microstructure array‐dielectric‐metal (MDM) structure, a novel metamaterial absorber integrated microfluidic (MAIM) sensor is proposed and demonstrated in terahertz (THz) range, where the dielectric layer of the MDM structure is hollow and acts as the microfluidic channel. Tuning the electromagnetic parameters of metamaterial absorber, greatly confined electromagnetic fields can be obtained in the channel resulting in significantly enhanced interaction between the analytes and the THz …

39、Generation of in-plane light beam with orbital angular momentum with an asymmetrical plasmonic waveg

Wanwan Liu, Xin Hu, Lin Jin, Xinxin Fu, Qin Chen.Plasmonics.2016/10

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Based on silicon plasmonic waveguide with asymmetrical metal and dielectric coatings, we show that in-plane light beam with orbital angular momentum (OAM) in its axis field component could be generated by forming a π/2 phase difference between two fundamental modes of the asymmetrical waveguide. At the same time, the transverse field components contain a spin angular momentum due to the polarization rotation in the asymmetrical waveguide. The whole structure is ultracompact with a footprint less than < 3 × 0.5 × 0.5 μm. The proposed method to generate OAM beam in a waveguide would be interesting for on-chip integrated optical tweezers, information processing, etc.

40、Nanoscale Printing Technique and its Applications in Nanophotonics

Huacun Wang, Long Wen, Xin Hu, Yan Yu, Yue Zhao, Qin Chen.Nano.2016/9

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“Printing” is an ancient technique for recording and publishing. Recently, this technique has extended its activities down to a nanometer scale. In this paper, we review the progress of the printing technique focusing on the most recent developments of one technique called “transfer printing” and its applications in nanophotonics.

41、Nanophotonic image sensors

Qin Chen, Xin Hu, Long Wen, Yan Yu, David RS Cumming.Small.2016/9

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The increasing miniaturization and resolution of image sensors bring challenges to conventional optical elements such as spectral filters and polarizers, the properties of which are determined mainly by the materials used, including dye polymers. Recent developments in spectral filtering and optical manipulating techniques based on nanophotonics have opened up the possibility of an alternative method to control light spectrally and spatially. By integrating these technologies into image sensors, it will become possible to achieve high compactness, improved process compatibility, robust stability and tunable functionality. In this Review, recent representative achievements on nanophotonic image sensors are presented and analyzed including image sensors with nanophotonic color filters and polarizers, metamaterial‐based THz image sensors, filter‐free nanowire image sensors and nanostructured‐based …

42、Electro-absorption modulator with dual carrier accumulation layers based on epsilon-near-zero ITO

Lin Jin, Qin Chen, Wanwan Liu, Shichao Song.Plasmonics.2016/8

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An electro-absorption modulator based on indium tin oxide is proposed by constructing a waveguide consisting of metal-dielectric-ITO-dielectric-Si stack. Applying a negative voltage bias on the ITO layer, carrier accumulation occurs at both dielectric-ITO interfaces, which dramatically changes the guided mode properties due to the epsilon-near-zero effect. By tuning the real part of the permittivity around zero, the guided plasmonic mode concentrates in either ITO or dielectric layers, resulting in a high propagation loss. These dual carrier accumulation layers significantly improve the extinction ratio of the modulator. A further improvement is obtained by using high refractive index dielectric thin layers, which provides a strong optical confinement in the carrier accumulation layers. The dual carrier accumulation layer device shows a 200 % increase of the modulation efficiency compared to a single accumulation …

43、Modulating spatial light by grating slot waveguides with transparent conducting oxides

Xin Hu, Qin Chen, Long Wen, Lin Jin, Huacun Wang, Wanwan Liu.IEEE Photonics Technology Letters.2016/8

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Transparent conducting oxides (TCOs) are emerging active materials for light modulating due to their special epsilon-near-zero effect. A novel spatial light modulating technique based on the guided mode resonance effect in a slot waveguide with TCOs is proposed, where both transmission and reflection can be manipulated by injecting or depleting carriers into the TCO layer. Temporal coupled mode theory and finite element method are used to analyze the light coupling and filtering. A modulation depth at 1550 nm as high as 0.85 is obtained due to the dramatic variations of modal properties in a TCO layer embedded slot waveguide. The wavelength bandwidth with a modulation depth above 0.5 is 8.6 nm. In addition, the resonant wavelength is sensitive to the bias on the TCO layer, which makes the device a tunable transmissive/reflective filter with a tuning range of 40 nm.

44、Ultrathin continuous lossy metal film for broadband light absorption and hot electron collection

Long Wen, Qin Chen.Journal of Photonics for Energy.2016/7

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A broadband perfect light absorption scheme relying on planar layers of lossy metallic and semiconductor films without structure pattering for hot electron photodetection is proposed and demonstrated. The nontrivial reflection phase shift occurring in the ultrathin lossy metal film is responsible for the strong resonance effects of the metal–semiconductor–metal (M-S-M) structures. Broadband and perfect light absorption is demonstrated experimentally for the platinum (Pt)—titanium dioxide ()—aluminum (Al) absorber, in which the ultrathin (10 nm) Pt layer electrically serves as the hot electron emitter. Under the monochromatic light illumination, the proposed M-S-M diode shows a clear hot-electron-based photoresponse.Long Wen, Qin Chen.Journal of Photonics for Energy.2016/7
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