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Hybrid External Cavity Laser with an Amorphous Silicon-Based Photonic Crystal Cavity Mirror
摘要： The authors present results on the performance of a hybrid external cavity photonic crystal laser-comprising semiconductor optical ampli?er, and a 2D photonic crystal cavity fabricated in low-temperature amorphous silicon. The authors demonstrate that lithographic control over amorphous silicon photonic crystal cavity-resonant wavelengths is possible, and that single-mode lasing at optical telecommunications wavelengths is possible on an amorphous silicon platform.
关键词： nanophotonics,silicon photonics,amorphous silicon,CMOS processing,photonic crystals,telecommunications,lasers
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Modeling Methodology for Determining Energy Collection Potential of Photovoltaics Applied To Curved Surfaces
摘要： Arrays of periodic one-dimensional nanomaterials offer tunable optical properties in terms of light–matter interaction which are attractive for designing efficient optoelectronic devices. This paper presents a fabrication of bottom-up grown nanopillar (NP) array solar cells based on n-i-p thin-film amorphous silicon using scaffolds of vertically aligned carbon nanotube (CNT) array. The effects of varying the CNT spacing over the range from 800 to 2000 nm on optical and electrical properties of the solar cells were investigated. The NP solar cell with CNT spacing of 800 nm exhibited ‘moth-eye’ broadband antireflection behavior, showing an average reflectance value lower than 10%. The enhanced optical absorption translated to significant enhancements in photocurrent and quantum efficiency compared to a conventional planar solar cell under low light condition. The open-circuit voltage (Voc) of the NP solar cell was found systematically correlated with the CNT spacing and the illumination condition. The results presented here is of importance for developing high efficiency one-dimensional nanostructured solar cells.
关键词： photovoltaic cells,nanostructured materials,nanophotonics,Amorphous silicon,carbon nanotube (CNT)
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - High-Speed Germanium Pin Photodiodes Integrated on Silicon-on-Insulator Nanophotonic Waveguides
摘要： Hetero-structured silicon-germanium-silicon photodetectors operating under low-reverse-voltages with high responsivity, fast response, and low dark-current levels are reported. A bit-error-rate of 10-9 is experimentally achieved for conventional data rates of 10, 20, and 25 Gbps, providing optical power sensitivities of -13.9, -12.7, and -11.3 dBm.
关键词： silicon nanophotonics,optical photodetectors,complementary metal-oxide-semiconductor technology,germanium,silicon-on-insulator
更新于2025-09-16 10:30:52
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A Plasmonic Paintera??s Method of Color Mixing for a Continuous Red-Green-Blue (RGB) Palette
摘要： The ability of mixing colors with remarkable results had long been exclusive to the talents of master painters. By finely combining colors at different amounts on the palette, intuitively, they obtain smooth gradients with any given color. Creating such smooth color variations through scattering by the structural patterning of a surface, as opposed to color pigments, has long remained a challenge. Here, we borrow from the painter’s approach and demonstrate color mixing generated by an optical metasurface. We propose a single-layer plasmonic color pixel and a method for nanophotonic structural color mixing based on the additive RGB color model. The color pixels consist of plasmonic nanorod arrays that generate vivid primary colors and enable independent control of color brightness without affecting chromaticity, by simply varying geometric in-plane parameters. By interleaving different nanorod arrays, we combine up to three primary colors on a single pixel. Based on this, two- and three-color mixing is demonstrated, enabling the continuous coverage of a plasmonic RGB color gamut and yielding a palette with a virtually unlimited number of colors. With this multi-resonant color pixel, we show the photorealistic printing of color and monochrome images at the nanoscale, with ultra-smooth transitions in color and brightness. Our color mixing approach can be applied to a broad range of scatterer designs and materials, and has the potential to be used for multi-wavelength color filters and dynamic photorealistic displays.
关键词： plasmonic color,nanophotonics,plasmonic lattice,color-printing,nanoantenna,structural color
更新于2025-09-16 10:30:52
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Dispersion tailoring of silicon nanowire optical rectangular waveguide (SNORW)
摘要： Dispersion analysis on silicon nanowire optical rectangular waveguide (SNORW) has been presented in this paper by guiding light inside low refractive index region. Dispersion engineering is an essential study to utilize any photonic integrated circuit-based waveguide in linear and nonlinear optical devices. This paper exhibits distinctive dispersion characteristics recognized in the wavelengths of S, C and L bands by tailoring physical parameters of SNORW. Modal investigation and numerical analysis have been carried out by finite element method (FEM), which shows that SNORW configuration enables the flat and low negative dispersion behavior. This paper also demonstrates the utilization of cladding materials and structural parameters of SNORW to tune the magnitude and behavior of dispersion for flat dispersion profile.
关键词： Silicon nanowire,Photonic integrated circuits,Optical waveguide,Dispersion,Silicon photonics,Photonic structure,Nanophotonics
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - All-Optical Ultrafast Control of Second Harmonic Generation in AlGaAs Nanopillars
摘要： All-dielectric nanophotonics has recently raised an increasing interest because the optical response of high-permittivity dielectric nanoparticles exhibits negligible dissipative losses and strong magnetic multipole resonances [1-4] in the visible and near-IR. We recently reported a second harmonic generation (SHG) conversion efficiency higher than 10-5 at (cid:79)= 1554 nm (pump intensity (cid:124) 1.6 GW/cm2; pulse width (cid:124) 150 fs; repetition rate = 80 MHz) in all-dielectric Al0.18Ga0.82As-on-AlOx nanodisks [5-7]. Such a remarkable efficiency is achieved thanks to the exploitation of magnetic and electric resonances emerging at coincidence with both the pump and SHG wavelength. In addition, the choice of both the pump and, consequently, the SHG ((cid:124) 777 nm) wavelength, set below the energy of the material bandgap, allow minimizing the two-photon absorption of the pump and the re-absorption of the SHG. Here, we demonstrate the potential for the all-optical modulation of the SHG. First, we study the behavior of the emitted SHG signal when the nanoantennas are concurrently illuminated with a low-power (< 300 (cid:80)W) continuous wave (CW) laser with energy above the bandgap ((cid:124) 3.2 eV, 405 nm wavelength). We observe variations in the SHG yield of the nanoantennas up to 60%. Figure 1a shows the SHG differential map acquired on an array of nanopillars with variable radius (r). Figure 1b shows the overall SHG intensity (dashed line) as well as the SHG modulation (solid blue line) as a function of r. While SHG from the smaller nanopillar (r = 205 nm) is decreased by about 60% under a 300 (cid:80)W CW pump beam, the 220-nm-radius nanopillar show a 30% SHG enhancement. We also investigated the ultrafast modulation of the SHG in a pump-probe experiment, where the pump is an ultrashort pulse at (cid:79)= 510 nm (above material bandgap), while the probe is a time-delayed pulse at (cid:79)= 1550 nm generating the SHG, to study the SHG dynamics when the pillars are brought out of equilibrium and a transient plasma is photoinjected in the dielectric. Time-traces of the SHG as a function of the pump-probe delay are shown in Figure 1c. We measured an ultrafast SHG quenching (< 0.5 ps) and slower (10 to 100 ps) recovery times, which strongly depend on the nanopillars, hence on the resonances involved. Our results allow gaining further insight into the photophysics of the nonlinear emission in these nanoscale systems and pave the way to the all-optical control of nanoscale nonlinear photonic devices for data storage with AlGaAs-on-insulator all-dielectric platforms.
关键词： Second harmonic generation,All-optical modulation,Nanopillars,All-dielectric nanophotonics,AlGaAs,SHG
更新于2025-09-12 10:27:22
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Knowledge Discovery in Nanophotonics Using Geometric Deep Learning
摘要： We present here a distinctive approach for using the intelligence aspects of artificial intelligence for knowledge discovery rather than the conventional task of device optimization in electromagnetic (EM) nanostructures. This approach uses training data obtained through full-wave EM simulations of a series of nanostructures to train geometric deep learning algorithms to assess the range of feasible responses as well as the feasibility of a desired response from a class of nanophotonic structures. To facilitate the knowledge discovery and reduce the computation complexity, our approach combines the dimensionality reduction technique (using an autoencoder) with convex-hull and one-class support-vector-machine (SVM) algorithms to find the range of the feasible responses in the latent (or the reduced) response space of the EM nanostructure. We show that by using a small set of training instances (compared to all possible structures), our approach can provide better than 95% accuracy in assessing the feasibility of a given response. More importantly, the one-class SVM algorithm can be trained to provide the degree of feasibility (or unfeasibility) of a response from a given nanostructure. This important information can be used to modify the initial structure to an alternative one that can enable an initially unfeasible response. To show the applicability of our approach, we apply it to two important classes of binary metasurfaces (MSs), formed by an array of plasmonic nanostructures, and periodic MSs formed by an array of dielectric nanopillars. In addition to theoretical results, we show the experimental results obtained by fabricating several MSs of the second class. Our theoretical and experimental results confirm the unique features of this approach for knowledge discovery in nanophotonics applications.
关键词： convex-hull,one-class SVM,geometric deep learning,knowledge discovery,nanophotonics,autoencoder,electromagnetic nanostructures
更新于2025-09-12 10:27:22
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Lightning-Rod Effect of Plasmonic Field Enhancement on Hydrogen-Absorbing Transition Metals
摘要： The plasmonic enhancement of electromagnetic ?eld energy density at the sharp tips of nanoparticles or nanoscale surface roughnesses of hydrogen-absorbing transition metals, Pd, Ti, and Ni, is quantitatively investigated. A large degree of energy focusing is observed for these transition metals in the microwave region, even surpassing the enhancement for noble metals according to the conditions. Pd, for instance, exhibits peak ?eld enhancement factors of 6000 and 2 × 108 in air for morphological aspect ratios of 10 and 100, respectively. Metal surfaces possibly contain such degrees of nano- or micro-scale native random roughnesses, and, therefore, the ?eld enhancement e?ect may have been unknowingly produced in existing electrical and optical systems. In addition, for future devices under development, particularly in hydrogen-related applications, it is desirable to design and optimize the systems, including the choice of materials, structures, and operating conditions, by accounting for the plasmonic local energy enhancement e?ect around the metal surfaces.
关键词： nuclear fusion,sensing,transition metal,surface plasmon,nanophotonics,energy device,hydrogen storage,nanoparticle
更新于2025-09-12 10:27:22
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Ultrafast Melting of Metal–Organic Frameworks for Advanced Nanophotonics
摘要： The conversion of metal–organic frameworks (MOFs) into derivatives with a well-defined shape and composition is considered a reliable way to produce efficient catalysts and energy capacitors at the nanometer scale. Yet, approaches based on conventional melting of MOFs provide the derivatives such as amorphous carbon, metal oxides, or metallic nanoclusters with an appropriate morphology. Here ultrafast melting of MOFs is utilized by femtosecond laser pulses to produce a new generation of derivatives with complex morphology and enhanced nonlinear optical response. It is revealed that such a nonequilibrium process allows conversion of interpenetrated 3D MOFs comprising flexible ligands into well-organized spheres with a metal oxide dendrite core and amorphous organic shell. The ability to produce such derivatives with a complex morphology is directly dependent on the electronic structure, crystal density, ligand flexibility, and morphology of initial MOFs. An enhanced second harmonic generation and three-photon luminescence are also demonstrated due to the resonant interaction of 100–1000 nm spherical derivatives with light. The results obtained are in the favor of new approaches for melting special types of MOFs for nonlinear nanophotonics.
关键词： ultrafast melting,femtosecond laser,nanophotonics,metal–organic framework,derivatives
更新于2025-09-12 10:27:22
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[ACS Symposium Series] Fundamentals and Applications of Phosphorus Nanomaterials Volume 1333 || Black Phosphorus Based Photodetectors
摘要： The layered two-dimensional (2D) black phosphorus (BP) has found significant applications in nanoelectronics and nanophotonics. In particular, it has been proven as a promising material for photodetectors due to its narrow direct bandgap ranging from 0.3 eV to 2 eV, high carrier mobility, modulation capability, and polarization sensitivity. The modulation capability of BP based photodetector is achieved by gate control using field effect transistor structure. Homojunction and heterojunction have been demonstrated to suppress dark current while enhancing carrier collection efficiency. Plasmonic effect and avalanche breakdown are exploited to boost the responsivity further. To extend the detection wavelength of BP, electric field modulation and arsenide doping are investigated, leading to a wide detection wavelength up to 8 μm. Owing to the ease of integrating BP with diverse substrates due to BP’s 2D nature, waveguide-integrated BP based photodetectors are realized in the near-infrared (NIR) for telecommnunication applications and in the mid-infrared (MIR) for on-chip sensing applications. High speed and high responsivity can be achieved by optimizing the device design. Despite that the mechanical robustness of BP on waveguide remains challenging, nevertheless, wafer-level growth of BP is highly desirable to realize scalable integration for mass production.
关键词： near-infrared,black phosphorus,waveguide-integrated,nanoelectronics,nanophotonics,photodetectors,mid-infrared
更新于2025-09-12 10:27:22