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Nanoelectrodes allow precise and quantitative measurements of important biological processes at the single living-cell level in real time. Cylindrical nanowire electrodes (NWEs) required for intracellular measurements create a great challenge for achieving excellent electrochemical and mechanical performances. Herein, we present a facile and robust solution to this problem based on a unique SiC-core-shell design to produce cylindrical NWEs with superior mechanical toughness provided by the SiC nano-core and an excellent electrochemical performance provided by the ultrathin carbon shell that can be used as such or platinized. The use of such NWEs for biological applications is illustrated by the first quantitative measurements of ROS/RNS in individual phagolysosomes of living macrophages. As the shell material can be varied to meet any specific detection purpose, this work opens up new opportunities to monitor quantitatively biological functions occurring inside cells and their organelles.

Coherent perfect absorber (CPA) was proposed as the time-reversed counterpart to laser: a resonator containing lossy medium instead of gain medium can absorb the coherent optical fields completely. Here, we exploit a monolayer graphene to realize the CPA in a nonresonant manner. It is found that quasi-CPA point exists in the terahertz regime for suspending monolayer graphene, and the CPA can be implemented with the assistance of proper phase modulation among two incident beams at the quasi-CPA frequencies. The graphene-based CPA is found of broadband angular selectivity: CPA point splits into two frequency bands for the orthogonal s and p polarizations at oblique incidence, and the two bands cover a wide frequency range starting from zero frequency. Furthermore, the coherent absorption can be tuned substantially by varying the gate-controlled Fermi energy. The findings of CPA with nonresonant graphene sheet can be generalized for potential applications in terahertz/infrared detections and signal processing with two-dimensional optoelectronic materials.

2D optics is gradually emerging as a frontier in modern optics. Plasmons in graphene provide a prominent platform for 2D optics in which the light is squeezed into atomic scale. This report highlights some recent progresses in graphene plasmons toward the 2D optics. The launch, observation, and advanced manipulation of propagating graphene plasmons for 2D optical circuits are described. Representative achievements associated with graphene metasurfaces, challenges, recent progresses like photoexcited graphene metasurfaces, and the transformation optics linking 2D to bulk optics with singularity are investigated.Abstract: Two-dimensional (2D) optics is gradually emerging as the frontier in modern optics. Plasmons in graphene provide a prominent platform for two-dimensional optics in which the light is squeezed into an atomic scale. This paper highlights some recent progresses in graphene plasmons towards the 2D optics. The launching, observation, and advanced manipulations of propagating graphene plasmons for 2D optical circuits are described. Representative achievements associated with graphene metasurfaces, challenges, recent progresses like photoexcited graphene metasurfaces and transformation optics linking 2D to bulk optics with singularity are investigated.

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A blue emission powder phosphor Sr 2 CeO 4 for field emission displays was prepared using a chemical coprecipitation technique, which is most suitable for large-scale production. The powders were fired at different temperatures to optimize the properties. Firing the powder at 1200 °C for 2 h gave the highest luminescence efficiency of 5.4 lm/W at 4 kV and 29.0 lm/W at 10 kV. The emission peak of this phosphor is at ϳ470 nm and Commission International de l'Eclairage coordinates are xϭ0. 19, yϭ0.26.

Artificially constructed metamaterials or metasurfaces with tailored resonant elements provide a revolutionary platform for controlling light at the subwavelength scale. Switchable or frequency-agile meta-devices are highly desirable in achieving more flexible functionalities and have been explored extensively by incorporating various materials, which respond to external stimuli. Graphene, a two-dimensional material showing extraordinary physical properties, has been found very promising for tunable meta-devices. However, the high intrinsic loss of graphene severely obstructs us from achieving high-quality resonance in various graphene metamaterials and metasurfaces, and the loss compensation can be considered as a straightforward strategy to take further advantages of enhanced light−graphene interactions. Here, we demonstrate that the photoexcited graphene, in which the quasi-Fermi energy of graphene changes corresponding to optical pumping, can boost the originally extremely weak magnetic resonance in a graphene split-ring metasurface, showing remarkable modulations in the transmission. Our work pioneers the possibilities of optically pumped graphene metasurfaces for significant enhancement of resonances and feasible modulations.