A Single-Photon Imager Based on Microwave Plasmonic Superconducting Nanowire

Detecting spatial and temporal information of individual photons by using single-photon-detector (SPD) arrays is critical to applications in spectroscopy, communication, biological imaging, astronomical observation, and quantum-information processing. Among the current SPDs1,detectors based on superconducting nanowires have outstanding performance2, but are limited in their ability to be integrated into large scale arrays due to the engineering difficulty of high-bandwidth cryogenic electronic readout3-8. Here, we address this problem by demonstrating a scalable single-photon imager using a single continuous photon-sensitive superconducting nanowire microwave-plasmon transmission line. By appropriately designing the nanowire's local electromagnetic environment so that the nanowire guides microwave plasmons, the propagating voltages signals generated by a photon-detection event were slowed down to ~ 2% of the speed of light. As a result, the time difference between arrivals of the signals at the two ends of the nanowire naturally encoded the position and time of absorption of the photon. Thus, with only two readout lines, we demonstrated that a 19.7-mm-long nanowire meandered across an area of 286 {\mu}m * 193 {\mu}m was capable of resolving ~590 effective pixels while simultaneously recording the arrival times of photons with a temporal resolution of 50 ps. The nanowire imager presents a scalable approach to realizing high-resolution photon imaging in time and space

A high performance, visible to mid-infrared photodetector based on graphene nanoribbons passivated with HfO2.

Graphene has drawn tremendous attention as a promising candidate for electronic and optoelectronic applications owing to its extraordinary properties, such as broadband absorption and ultrahigh mobility. Nevertheless, the absence of a bandgap makes graphene unfavorable for digital electronic or photonic applications. Although patterning graphene into nanostructures with the quantum confinement effect is able to open a bandgap, devices based on these graphene nanostructures generally suffer from low carrier mobility and scattering losses. In this paper, we demonstrated that encapsulation of an atomic layer deposited high-quality HfO2 film will greatly enhance the carrier mobility and decrease the scattering losses of graphene nanoribbons, because this high-k dielectric layer weakens carrier coulombic interactions. In addition, a photodetector based on HfO2 layer capped graphene nanoribbons can cover broadband wavelengths from visible to mid-infrared at room temperature, exhibiting ∼10 times higher responsivity than the one without a HfO2 layer in the visible regime and ∼8 times higher responsivity in the mid-infrared regime. The method employed here could be potentially used as a general approach to improve the performance of graphene nanostructures for electronic and optoelectronic applications

Dielectric multi-momentum meta-transformer in the visible

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Effect of carbon nanotubes on the curing dynamics and network formation of cyanate ester resin

This paper is closed access.The effect of a pristine carbon nanotube (CNT), and three functionalised carbon nanotubes on the curing dynamics and network formation of a cyanate ester resin (CY), was investigated by means of differential scanning calorimetry (DSC), modulated temperature differential scanning calorimetry (MTDSC), field emission gun scanning electron microscopy (FEGSEM), Fourier transform infrared (FTIR) and Raman spectroscopies. Incorporation of the various carbon nanotubes showed different accelerating effects on cure of the CY. Addition of the pristine multi-walled carbon nanotube (MWCNT) did not show a prominent accelerating effect, whilst a carboxyl group functionalised multi-wall nanotube (MWCNT-COOH) displayed the greatest accelerating effect. For a hydroxyl group functionalised multi-walled carbon nanotube (MWCNT-OH)/CY system, the most pronounced accelerating effect was observed when 1 wt% to 2 wt% MWCNT-OH was added. Nano-scale dispersion of both the pristine and the functionalised multi-walled carbon nanotubes in the CY matrix was observed by using FEG-SEM. In contrast, micro-scale aggregation happened in a SWCNT-OH/CY system. The FTIR spectra monitored the formation of triazine rings in the CY and its composites with CNTs. The FTIR results indicated that the CNTs reacted with the cyanate groups of the CY to form oxime C=N-O bonds. The up-shifting of the bands for CNTs in Raman spectra confirmed nano-scale dispersion of MWCNTs in the CY matrix and strong interaction between the MWCNTs and the CY