Detection of photonic orbital angular momentum with micro- and nano-optical structures
Chenhao WAN, Guanghao RUI, Jian CHEN, Qiwen ZHAN
Front. Optoelectron.. 2019, 12 (1): 88-96.
Light with an optical orbital angular momentum (OAM) has attracted an increasing amount of interest and has found its way into many disciplines ranging from optical trapping, edge-enhanced microscopy, high-speed optical communication, and secure quantum teleportation to spin-orbital coupling. In a variety of OAM-involved applications, it is crucial to discern different OAM states with high fidelity. In the current paper, we review the latest research progress on OAM detection with micro- and nano-optical structures that are based on plasmonics, photonic integrated circuits (PICs), and liquid crystal devices. These innovative OAM sorters are promising to ultimately achieve the miniaturization and integration of high-fidelity OAM detectors and inspire numerous applications that harness the intriguing properties of the twisted light.
Two-dimensional material functional devices enabled by direct laser fabrication
Tieshan YANG, Han LIN, Baohua JIA
Front. Optoelectron., 2018, 11 (1): 2-22.
During the past decades, atomically thin, two-dimensional (2D) layered materials have attracted tremendous research interest on both fundamental properties and practical applications because of their extraordinary mechanical, thermal, electrical and optical properties, which are distinct from their counterparts in the bulk format. Various fabrication methods, such as soft-lithography, screen-printing, colloidal-templating and chemical/dry etching have been developed to fabricate micro/nanostructures in 2D materials. Direct laser fabrication with the advantages of unique three-dimensional (3D) processing capability, arbitrary-shape designability and high fabrication accuracy up to tens of nanometers, which is far beyond the optical diffraction limit, has been widely studied and applied in the fabrication of various micro/nanostructures of 2D materials for functional devices. This timely review summarizes the laser-matter interaction on 2D materials and the significant advances on laser-assisted 2D materials fabrication toward diverse functional photonics, optoelectronics, and electrochemical energy storage devices. The perspectives and challenges in designing and improving laser fabricated 2D materials devices are discussed as well.
Dipole-fiber system: from single photon source to metadevices
Shaghik ATAKARAMIANS, Tanya M. MONRO, Shahraam AFSHAR V.
Front. Optoelectron., 2018, 11 (1): 30-36.
Radiation of an electric dipole (quantum emitter) in vicinity of optical structures still attracts great interest due to emerging of novel application and technological advances. Here we review our recent work on guided and radiation modes of electric dipole and optical fiber system and its applications from single photon source to metadevices. We demonstrate that the relative position and orientation of the dipole and the core diameter of the optical fiber are the two key defining factors of the coupled system application. We demonstrate that such a coupled system has a vast span of applications in nanophotonics; a single photon source, a high-quality factor sensor and the building block of metadevices.
Longitudinal twinning α-In2Se3 nanowires for UV-visible-NIR photodetectors with high sensitivity
Zidong ZHANG, Juehan YANG, Fuhong MEI, Guozhen SHEN
Front. Optoelectron., 2018, 11 (3): 245-255.
我们合成了孪晶面的纵向孪晶α-In2Se3纳米线，用于制作高性能单纳米线光探测器。合成的α-In2Se3纳米线显示出典型的n型半导体特性，具有23.1 cm2·V−1·S−1 的电子迁移率和300-1100nm的宽光谱响应，覆盖紫外-可见-近红外(UV-visible-NIR)波段。此外，所制作的光探测器显示了的高达8.57 × 105 A·W−1的响应度和8.8 × 107%的外量子效率，在3V偏压和600nm光照下，探测率为1.58 × 1012 Jones，远高于以前报道的In2Se3纳米结构，这归因于孪晶面的界面缺陷效应。研究结果表明了纵向孪晶α-In2Se3纳米线进一步应用于高性能宽带探测器及其他光电子器件的巨大潜力。
Longitudinal twinning α-In2Se3 nanowires with the twin plane were synthesized to fabricate high performance single nanowire based photodetectors. As-synthesized α-In2Se3 nanowire exhibited typical n-type semiconducting behavior with an electron mobility of 23.1 cm2·V−1·S−1 and a broadband spectral response from 300 to 1100 nm, covering the ultraviolet-visible-near-infrared (UV-visible-NIR) region. Besides, the fabricated device showed a high responsivity of 8.57 × 105 A·W−1, high external quantum efficiency up to 8.8 × 107% and a high detectivity of 1.58 × 1012 Jones under 600 nm light illumination at a basis of 3 V, which are much higher than previously reported In2Se3 nanostructures due to the interface defect effect of the twin plane. The results indicated that the longitudinal twinning α-In2Se3 nanowires have immense potential for further applications in highly performance broadband photodetectors and other optoelectronic devices.
Luminescent disordered nanostructures: synthesis and characterization of CdSe nano-agglomerates
Ruiqing HU, Yifeng SHI, Haifeng BAO
Front. Optoelectron., 2018, 11 (4): 385-393.
A disorderly nanostructured CdSe nano-agglomerates (NAs) with tunable emission are synthesized in aqueous solution. Although the CdSe NAs have diameters of about 20 nm that are larger than the Bohr radius of the crystal bulk, they show size-dependent emission similar to the CdSe nanocrystals. The CdSe NAs represent a collective energy state based on Anderson localization.
BiOI/WO3 photoanode with enhanced photoelectrochemical water splitting activity
Weina SHI, Xiaowei LV, Yan SHEN
Front. Optoelectron., 2018, 11 (4): 367-374.
本文报道了一种新型的BiOI/WO3复合光电阳极，它是通过电沉积方法将BiOI沉积到WO3纳米薄片上制成的。我们研究了可见光照射下BiOI/WO3电极用于水分解的光电化学行为，结果表明，在1.23V电压下，BiOI/WO3光电阳极获得了1.21 mA·cm−2的光电流密度，高于可逆氢电极的情况，而后者又高于纯WO3纳米薄片电极的情况（0.67 mA·cm−2）。用于水分解的BiOI/WO3电极所具有的增强光电化学行为归因于其光吸收范围的扩展和便于光生载流子的分离。
This work reports on a novel BiOI/WO3 composite photoanode, which was fabricated by depositing BiOI onto a WO3 nanoflake electrode through a electrodeposition method. The photoelectrochemical (PEC) activity of the BiOI/WO3 electrode for water splitting under visible-light irradiation was evaluated. The results show that the BiOI/WO3 photoanode achieved a photocurrent density of 1.21 mA·cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE), which was higher than that of the bare WO3 nanoflake electrode (0.67 mA·cm−2). The enhanced PEC acticity of BiOI/WO3 for water splitting can be attributed to the expansion of light absorption range as well as the facilitated separation of photo-generated carriers.
ZnO/Nb2O5 core/shell nanorod array photoanode for dye-sensitized solar cells
Xiaoyan HU, Heng WANG
Front. Optoelectron., 2018, 11 (3): 285-290.
本文中，我们合成了ZnO/Nb2O5 核壳纳米棒阵列并将其用于染料敏化太阳能电池（DSSC）的光电阳极。我们首先采用水热法在掺氟氧化锡(FTO)玻璃上合成了ZnO纳米棒阵列，然后在NbCl5溶液中通过溶剂热反应直接制备了ZnO/Nb2O5 核壳纳米棒阵列。扫描电镜和透射电镜图像显示ZnO纳米棒均匀地包裹了30-40nm的Nb2O5壳层，光伏特性测试结果表明基于ZnO/Nb2O5 核壳纳米棒光电阳极的器件效率提高至1.995%，远高于纯纳米棒光电阳极DSSC 0.856%的效率。这一结果证明包裹Nb2O5壳层可以改善ZnO纳米棒的光伏特性。
In this paper, ZnO/Nb2O5 core/shell nanorod arrays were synthesized and used as photoanodes for dye-sensitized solar cells (DSSCs). We first synthesized ZnO nanorod array on fluorine-doped tin oxide (FTO) glasses by a hydrothermal method, and then ZnO/Nb2O5 core/shell nanorod array was directly obtained via solvothermal reaction in NbCl5 solution. The scanning electron microscope (SEM) and transmission electron microscope (TEM) images revealed that the ZnO nanorods were uniformly wrapped by Nb2O5 shell layers with a thickness of 30–40 nm. Photovoltaic characterization showed that the device based on ZnO/Nb2O5 core/shell nanorod photoanode exhibited an improved efficiency of 1.995%, which was much higher than the efficiency of 0.856% for the DSSC based on bare ZnO nanorod photoanode. This proved that the photovoltaic performance of ZnO nanorods could be improved by wrapping with Nb2O5 shells.