Local and Nonlocal Optically Induced Transparency Effects in Graphene–Silicon Hybrid Nanophotonic Integrated Circuits

Graphene is well-known as a two-dimensional sheet of carbon atoms arrayed in a honeycomb structure. It has some unique and fascinating properties, which are useful for realizing many optoelectronic devices and applications, including transistors, photodetectors, solar cells, and modulators. To enhance light–graphene interactions and take advantage of its properties, a promising approach is to combine a graphene sheet with optical waveguides, such as silicon nanophotonic wires considered in this paper. Here we report <i>local</i> and <i>nonlocal</i> optically induced transparency (OIT) effects in graphene–silicon hybrid nanophotonic integrated circuits. A low-power, continuous-wave laser is used as the pump light, and the power required for producing the OIT effect is as low as ∼0.1 mW. The corresponding power density is several orders lower than that needed for the previously reported saturated absorption effect in graphene, which implies a mechanism involving light absorption by the silicon and photocarrier transport through the silicon–graphene junction. The present OIT effect enables low power, all-optical, broadband control and sensing, modulation and switching <i>locally</i> and <i>nonlocally</i>

High-Bandwidth Zero-Biased Waveguide-Integrated p‑n Homojunction Graphene Photodetectors on Silicon for a Wavelength Band of 1.55 μm and Beyond

The p-n homojunction graphene photodetectors (GPDs) based on the photothermoelectric (PTE) effect have drawn much attention for featuring zero-bias operation (i.e., zero dark current) with a bandwidth of tens of GHz. However, most waveguide-integrated GPDs were demonstrated for the 1.55 μm wavelength band. Here, we realize high-performance silicon waveguide integrated GPDs enabling efficient light absorption at both wavelength bands of 1.55 and 2 μm. The broadband operation of the present PTE GPDs is analyzed theoretically and experimentally. When operating at 1.55 μm, the GPD typically exhibits a responsivity of ∼2.81 V/W and a 3 dB bandwidth of >40 GHz (setup-limited) under zero bias. When the GPDs operate at 2 μm under zero bias, the responsivity is about 2.78–4 V/W and the 3 dB bandwidth is >22 GHz (setup-limited). The measured linear dynamic range is over 24 dB for both wavelength bands of 1.55 and 2 μm. The present high-performance waveguide-integrated GPD provides a promising option for the applications of silicon photonics beyond 1.55 μm, such as optical communications, photonics sending, etc

Changes in iTRAQ-Based Proteomic Profiling of the Cladoceran <i>Daphnia magna</i> Exposed to Microcystin-Producing and Microcystin-Free <i>Microcystis aeruginosa</i>

Global warming and increased nutrient fluxes cause cyanobacterial blooms in freshwater ecosystems. These phenomena have increased the concern for human health and ecosystem services. The mass occurrences of toxic cyanobacteria strongly affect freshwater zooplankton communities, especially the unselective filter feeder <i>Daphnia</i>. However, the molecular mechanisms of cyanobacterial toxicity remain poorly understood. This study is the first to combine the established body growth rate (BGR), which is an indicator of life-history fitness, with differential peptide labeling (iTRAQ)-based proteomics in <i>Daphnia magna</i> influenced by microcystin-producing (MP) and microcystin-free (MF) <i>Microcystis aeruginosa</i>. A significant decrease in BGR was detected when <i>D. magna</i> was exposed to MP or MF <i>M. aeruginosa</i>. Conducting iTRAQ proteomic analyses, we successfully identified and quantified 211 proteins with significant changes in expression. A cluster of orthologous groups revealed that <i>M. aeruginosa</i>-affected differential proteins were strongly associated with lipid, carbohydrate, amino acid, and energy metabolism. These parameters could potentially explain the reduced fitness based on the cost of the substance metabolism

Supplement 1: All-optical graphene modulator based on optical Kerr phase shift

Supplemental document for all-optical graphene modulator based on optical Kerr phase shift. Originally published in Optica on 20 May 2016 (optica-3-5-541

Supplementary document for Breaking the bandwidth limit of a high-quality-factor ring modulator based on thin-film lithium niobate - 6063603.pdf

Supplemental Documen