Terahertz nanofuse by a single nanowire-combined nanoantenna.

We propose a terahertz nanofuse through irreversible modulations in transmitted terahertz using nanowires-combined nanoantenna structures. Semiconductor and metal nanowires show irreversible reconfiguration in their geometry at an incident field of 20 kV/cm. The concept can be explained by terahertz-field-induced ionization or electromigration.

Colloidal MoS van der Waals Template for Growing Highly Uniform Nanomaterials.

The van der Waals (vdW) structures of transition metal dichalcogenides (TMDCs) have been studied extensively owing to the excellent electronic, optoelectronic, and catalytic performance with the atomic-scale sharpness of the interfaces. In addition, the presence of substitution and redox reactions in the vdW gaps also provides huge potential to be employed as a nanoscale reactor. Herein, the vdW gap of colloidal MoS is reported as a natural template for the formation of CoMo bimetallic oxide nanoparticles (BMONPs) with highly uniform size (∼4 nm), which resulted in further synthesis of the thin multiwalled carbon nanotubes with extremely narrow diameter distribution.

Author Correction: Graphene-assisted biosensing based on terahertz nanoslot antennas.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Graphene-assisted biosensing based on terahertz nanoslot antennas.

We report on improvement of sensitivity for molecular detection utilizing terahertz time domain spectroscopy. Based on confining and enhancing electromagnetic field with metallic nanoslot antennas, we additionally employ monolayer graphene sheet whose edge and hydrophobic surface nature lead to increase detecting performance. Terahertz transmittance in monolayer graphene/metallic nanoslot structure exhibits more unambiguous change after lactose molecules are attached, compared to that in metallic nanoslot structure without monolayer graphene.

Terahertz rectification in ring-shaped quantum barriers.

Tunneling is the most fundamental quantum mechanical phenomenon with wide-ranging applications. Matter waves such as electrons in solids can tunnel through a one-dimensional potential barrier, e.g.

Terahertz Nanoprobing of Semiconductor Surface Dynamics.

Most semiconductors have surface dynamics radically different from its bulk counterpart due to surface defect, doping level, and symmetry breaking. Because of the technical challenge of direct observation of the surface carrier dynamics, however, experimental studies have been allowed in severely shrunk structures including nanowires, thin films, or quantum wells where the surface-to-volume ratio is very high. Here, we develop a new type of terahertz (THz) nanoprobing system to investigate the surface dynamics of bulk semiconductors, using metallic nanogap accompanying strong THz field confinement.

Quantum dots-nanogap metamaterials fabrication by self-assembly lithography and photoluminescence studies.

We present a new and versatile technique of self-assembly lithography to fabricate a large scale Cadmium selenide quantum dots-silver nanogap metamaterials. After optical and electron microscopic characterizations of the metamaterials, we performed spatially resolved photoluminescence transmission measurements. We obtained highly quenched photoluminescence spectra compared to those from bare quantum dots film.

Plasmon enhanced terahertz emission from single layer graphene.

We show that surface plasmons, excited with femtosecond laser pulses on continuous or discontinuous gold substrates, strongly enhance the generation and emission of ultrashort, broadband terahertz pulses from single layer graphene. Without surface plasmon excitation, for graphene on glass, 'nonresonant laser-pulse-induced photon drag currents' appear to be responsible for the relatively weak emission of both s- and p-polarized terahertz pulses. For graphene on a discontinuous layer of gold, only the emission of the p-polarized terahertz electric field is enhanced, whereas the s-polarized component remains largely unaffected, suggesting the presence of an additional terahertz generation mechanism.

Operation of a wet near-field scanning optical microscope in stable zones by minimizing the resonance change of tuning forks.

A resonant shift and a decrease of resonance quality of a tuning fork attached to a conventional fiber optic probe in the vicinity of liquid is monitored systematically while varying the protrusion length and immersion depth of the probe. Stable zones where the resonance modification as a function of immersion depth is minimized are observed. A wet near-field scanning optical microscope (wet-NSOM) is operated for a sample within water by using such a stable zone.

Simple and reliable light launch from a conventional single-mode fiber into a helical-core fiber through an adiabatically tapered splice.

We propose a simple and efficient light launch scheme for a helical-core fiber (HCF) by using an adiabatically tapered splice technique, through which we overcome its inherent difficulty with light launch owing to the large lateral offset and angular tilt of its core. We experimentally demonstrate single-mode excitation in the HCF in this configuration, which yields the coupling efficiency of around -5.9 dB (26%) for a ~1.