Graphene was the first two dimension (2D) material demonstrated as temporal modulator in fiber laser system more than a decade ago. Following its success, other types of 2D materials with comparable ...and superior performance were discovered. In this review, we outlined the types of optical modulation into wavelength, amplitude, polarization, phase and temporal modulation. We also discussed each modulation working principles along with its fiber laser configuration. Additionally, we compiled each modulator’s performance based on a wide range of 2D materials that were published recently. Some novel and emerging materials such as quantum dot (QD), one dimension (1D), three dimension (3D), composite and organic materials were highlighted.
Non‐volatile, bidirectional, all‐optical switching in a phase‐change metamaterial delivers high‐contrast transmission and reflection modulation at near‐ to mid‐infrared wavelengths in device ...structures down to ≈1/27 of a wavelength thick.
Phosphorene, mono/few‐layered black phosphorous with advantages of tunable energy bandgaps and strong light–matter interaction, is fabricated by electrochemical intercalation with large area (≈3 µm) ...and controllable thickness (mainly four layers). Thanks to the direct gap and resonant absorption of four‐layer phosphorene at the telecommunication band, all‐optical thresholding and optical modulation are demonstrated for optical communications by using few‐layer phosphorene‐decorated microfibers. This device is experimentally verified as an efficient noise suppressor that can enhance the signal‐to‐noise ratio and reshape the deteriorated signal pulse, and also as an optical modulator that can switch the signal on/off by pumping light. The findings, as the first prototypic device of all‐optical thresholding and optical modulation, might facilitate the development of phosphorene‐based optical communication technologies.
Few‐layer phosphorene (FL‐P) is fabricated by electrochemical intercalation with large area and controllable thickness. All‐optical thresholding and optical modulation are demonstrated for optical communications by using FL‐P‐decorated microfibers, which can dramatically suppress noise level and switch the signal on/off by pumping light. The first prototypic devices with these two functions might facilitate the development of phosphorene‐based optical communication technologies.
The optical Kerr nonlinearity of plasmonic metals provides enticing prospects for developing reconfigurable and ultracompact all‐optical modulators. In nanostructured metals, the coherent coupling of ...light energy to plasmon resonances creates a nonequilibrium electron distribution at an elevated electron temperature that gives rise to significant Kerr optical nonlinearities. Although enhanced nonlinear responses of metals facilitate the realization of efficient modulation devices, the intrinsically slow relaxation dynamics of the photoexcited carriers, primarily governed by electron–phonon interactions, impedes ultrafast all‐optical modulation. Here, femtosecond (≈190 fs) all‐optical modulation in plasmonic systems via the activation of relaxation pathways for hot electrons at the interface of metals and electron acceptor materials, following an on‐resonance excitation of subradiant lattice plasmon modes, is demonstrated. Both the relaxation kinetics and the optical nonlinearity can be actively tuned by leveraging the spectral response of the plasmonic design in the linear regime. The findings offer an opportunity to exploit hot‐electron‐induced nonlinearities for design of self‐contained, ultrafast, and low‐power all‐optical modulators based on plasmonic platforms.
Exchange of hot electrons at the interface of plasmonic metals and electron acceptor materials is employed to enable an electron‐dominated relaxation pathway for demonstration of femtosecond (≈190 fs) all‐optical modulation in plasmonic systems. Relaxation dynamics and optical nonlinearity are actively tuned by leveraging the linear spectral response of a designed plasmonic lattice suitable for all‐optical data processing.
WO3·2H2O film with porous structure was grown on indium tin oxide (ITO) glass by a simple constant current electrodeposition (CCE). The as-grown WO3·2H2O film shows a loose and porous structure, ...which is formed by the accumulation of large size nanoparticles. For comparison, amorphous WO3·xH2O film was prepared by constant voltage electrodeposition (CVE). Both the films prepared by CCE and CVE are hydrated oxides instead of simple oxides, which is proved by thermal analysis. A large optical modulation of 86.3% at 550 nm and a high coloration efficiency of 178.8 cm2 C−1 are achieved for the WO3·2H2O film. Additionally, the as-prepared film also shows a good cycling stability: the film exhibits an optical modulation of 75.6% after 500 cycles (retaining 87.6% of its initial optical modulation). Excellent electrochromic properties should be attributed to the porous structure of the WO3·2H2O film, which brings more electrochemical active sites for insertion and extraction of ions.
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•Porous WO3·2H2O film were obtained by low-cost and simple electrodeposition method.•The as-prepared WO3·2H2O film exhibits large optical modulation and high coloration efficiency.•Both the films prepared by constant current electrodeposition and constant voltage electrodeposition are hydrated oxides.
Biofabrication
In article number 2204301, Marcy Zenobi‐Wong and co‐workers use Filamented Light (FLight) biofabrication to create hydrogel constructs containing ultrahigh‐aspect‐ratio microfilaments. ...FLight biofabrication is both fast and biocompatible. Microfilaments and associated microchannels provide effective topological guidance cues to instruct cell migration, alignment, and extracellular matrix deposition of resident cells.
What is LiFi? Haas, Harald; Liang Yin; Yunlu Wang ...
Journal of lightwave technology,
03/2016, Letnik:
34, Številka:
6
Journal Article
Recenzirano
This paper attempts to clarify the difference between visible light communication (VLC) and light-fidelity (LiFi). In particular, it will show how LiFi takes VLC further by using light emitting ...diodes (LEDs) to realise fully networked wireless systems. Synergies are harnessed as luminaries become LiFi attocells resulting in enhanced wireless capacity providing the necessary connectivity to realise the Internet-of-Things, and contributing to the key performance indicators for the fifth generation of cellular systems (5G) and beyond. It covers all of the key research areas from LiFi components to hybrid LiFi/wireless fidelity (WiFi) networks to illustrate that LiFi attocells are not a theoretical concept any more, but at the point of real-world deployment.
Magneto‐optical (MO) modulation of the photonic spin Hall effect (PSHE) of transmitted light in graphene–substrate system in terahertz region is proposed. The expressions for PSHE shifts of ...left‐handed circularly polarized (LHCP) and right‐handed circularly polarized (RHCP) components are derived based on angular spectrum analysis. PSHE shifts and their physical mechanisms are discussed in detail in the presence of different relaxation time and Fermi energy of graphene based on simulation results. The potential applications of MO‐modulated PSHE in multichannel switch and barcode encryption are also proposed and discussed. The MO‐modulated PSHE in graphene–substrate system provides a new mechanism to realize photonic devices in the terahertz region.
Magneto‐optical modulation of photonic spin Hall effect (PSHE) in graphene–substrate system is proposed in terahertz region. PSHE shifts and their physical mechanisms are discussed in detail in the presence of different relaxation time and Fermi energy of graphene. Its potential applications in multichannel switch and barcode encryption provide a new mechanism of photonic devices in terahertz region.
High-speed digital-to-analog converters (DACs) are essential in advanced optical transmission systems, utilizing multilevel modulation formats and pulse-shaping technologies. Analog bandwidth of DACs ...is one of the major limiting factors for the system capacity. In this paper, we present an idea to extend the analog bandwidth of DACs by utilizing a digital preprocessor, two sub-DACs, and an analog multiplexer (AMUX). The AMUX is a high-speed linear selector, and a frequency-domain interpretation of the AMUX's function has led us to devise the digital preprocessing for a seamless extension of the analog bandwidth. This configuration, which we call a digital-preprocessed analog-multiplexed DAC, provides nearly doubled analog bandwidth compared to that of each subDAC with a symmetric configuration. The idea was verified by a transmission experiment with 160-Gb/s 80-Gbaud Nyquist four-level pulse amplitude modulation. In the experiment, we used subDACs with an analog bandwidth of ~20 GHz in combination with an AMUX fabricated with InP heterojunction bipolar transistor technology.
A smart window that dynamically modulates light transmittance is crucial for building energy efficiently, and promising for on‐demand optical devices. The rapid development of technology brings out ...different categories that have fundamentally different transmittance modulation mechanisms, including the electro‐, thermo‐, mechano‐, and photochromic smart windows. In this review, recent progress in smart windows of each category is overviewed. The strategies for each smart window are outlined with particular focus on functional materials, device design, and performance enhancement. The advantages and disadvantages of each category are summarized, followed by a discussion of emerging technologies such as dual stimuli triggered smart window and integrated devices toward multifunctionality. These multifunctional devices combine smart window technology with, for example, solar cells, triboelectric nanogenerators, actuators, energy storage devices, and electrothermal devices. Lastly, a perspective is provided on the future development of smart windows.
The smart window is a promising technology to reduce building energy consumption by dynamically controlling the indoor solar irradiation. In this review, the most recent progress in strategies for electro‐, thermo‐, mechano‐, and photochromics is summarized. A summary of integrated devices toward multifunctionality is presented as well as a perspective on future development.
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