Highly efficient vortex four-wave mixing in asymmetric semiconductor quantum wells

© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement Orbital angular momentum (OAM) is an important property of vortex light, which provides a valuable tool to manipulate the light-matter interaction in the study of classical and quantum optics. Here we propose a scheme to generate vortex light fields via four-wave mixing (FWM) in asymmetric semiconductor quantum wells. By tailoring the probe-field and control-field detunings, we can effectively manipulate the helical phase and intensity of the FWM field. Particularly, when probe field and control field have identical detuning, we find that both the absorption and phase twist of the generated FWM field are significantly suppressed. Consequently, the highly efficient vortex FWM is realized, where the maximum conversion efficiency reaches around 50%. Our study provides a tool to transfer vortex wavefronts from input to output fields in an efficient way, which may find potential applications in solid-state quantum optics and quantum information processing

Facilitation-Induced Transparency and Single-Photon Switch with Dual-Channel Rydberg Interactions

We investigate facilitation-induced transparency (FIT) enabled by strong and long-range Rydberg atom interactions between two spatially separated optical channels. In this setting, the resonant two-photon excitation of Rydberg states in a target channel is conditioned by a single Rydberg excitation in a control channel. Through the contactless coupling enabled by the Rydberg interaction, the optical transparency of the target channel can be actively manipulated by steering the optical detuning in the control channel. By adopting a dressed-state picture, we identify two different interference pathways, in which one corresponds to Rydberg blockade and an emergent one results from facilitation. We show that the FIT is originated from the Rydberg interaction and the quantum interference effect between the two pathways, which is different from conventional electromagnetically induced transparency realized by single-body laser-atom coupling. We find that the FIT in such a dual-channel setting is rather robust, insensitive to changes of systemic parameters, and can be generalized to multichannel settings. Moreover, we demonstrate that such a FIT permits the realization of controllable single-photon switches, which also paves a route to detect Rydberg facilitation by using optical absorption spectra. Our study contributes to current efforts in probing correlated many-body dynamics and developing single-photon quantum devices based on Rydberg atom ensembles

HPV E6 induces eIF4E transcription to promote the proliferation and migration of cervical cancer

AbstractIncreasing evidence has placed eukaryotic translation initiation factor 4E (eIF4E) at the hub of tumor development and progression. Several studies have reported that eIF4E is over-expressed in cervical cancer; however, the mechanism remains elusive. The results of this study further confirm over-expression of eIF4E in cervical cancer tumors and cell lines, and we have discovered that the transcription of eIF4E is induced by protein E6 of the human papillomavirus (HPV). Moreover, regulation of eIF4E by E6 significantly influences cell proliferation, the cell cycle, migration, and apoptosis. Therefore, eIF4E emerges as a key player in tumor development and progression and a potential target for CC treatment and prevention

Robust Rydberg gate via Landau-Zener control of Förster resonance

In this paper, we propose a scheme to implement the two-qubit controlled-Z gate via the Stark-tuned Förster interaction of Rydberg atoms, where the Förster defect is driven by a time-dependent electric field of a simple sinusoidal function while the matrix elements of the dipole-dipole interaction are time independent. It is shown that when the system is initially in a specific state, it makes a cyclic evolution after a preset interaction time, returning to the initial state, but picks up a phase, which can be used for realizing a two-atom controlled-Z gate. Due to the interference of sequential Landau-Zener transitions, the population and phase of the state is quasideterministic after the cyclic evolution and therefore the gate fidelity is insensitive to fluctuations of the interaction time and the dipole-dipole matrix elements. Feasibility of the scheme realized with Cs atoms is discussed in detail, which shows that the two-qubit gate via Landau-Zener control can be realized with the state-of-the-art experimental setup

Exploration of Direct-Ink-Write 3D Printing in Space: Droplet Dynamics and Patterns Formation in Microgravity

As a simple, fast and effective 3D printing method, direct-ink-writing (DIW) has potential applications in repairing the circuit board in orbit, printing the wearable devices for the astronaut, and producing the solar cells for the energy supply in space. To expand the DIW technology to space, we designed the colloidal material box (CMB) as the prototype printer of DIW and verified its applicability in the Chinese SJ-10 satellite. The colloidal suspensions was adopted as a diluted ink model to investigate two key processes of DIW under microgravity environment: manipulation of the droplet and formation of the patterns. We have showed the dynamics of the droplet, which would determine the size of the features, could be controlled through tuning the wettability of the needles and the solid surface. Compared to the ground, the "coffee ring" effect was weakened for the drying patterns because of strong interfacial effect under weightless conditions. We have found that fast evaporation could assist for fabricating more uniform and ordered structures

Self-Assembly of Ordered Microparticle Monolayers from Drying a Droplet on a Liquid Substrate

Drying droplets on solid substrates has always formed a nonuniform and disordered "coffee ring" stain, which has a great negative effect on the application of inject printing and colloidal assembly. We obtain a macrouniform and micro-ordered pattern through evaporation of a colloidal droplet resting on a liquid substrate. The evaporative convection and the capillary forces were responsible for the formation of the ordered structures, which assembled into a monolayer pattern at the liquid-air interface under the action of the weak capillary flow and shrinkage of the triple line. The central bump deposits with disordered particle stacking on the liquid-liquid interface could be attributed to the fast meeting of the descending particles (gravitational sedimentation) and ascending liquid-liquid interface; they would scatter on the ordered monolayer structure and form the final uniform pattern

A methodology for the analysis of the influence of odors on the users' evaluation of industrial products

The sense of smell has a great importance in our daily living: today pleasant odors are used to elicit positive emotions in users. In the marketing area, a lot of works have been done concerning the use of odors for communicating information related to products as household cleaners and foods. In the area of Virtual Reality (VR), several researches have focused on presenting odors in virtual environments. This approach can represent an easy and flexible means for evaluating industrial products characteristics. This research work aims at evaluating in which way odors can influence the users’ evaluation of products and if studies on the influence of odors on the users’ evaluation of products in a VR environment and in a real environment can be comparable. For this purpose, an experimental framework has been defined, a wearable olfactory display has been developed and experimental testing sessions have been performed

Spreading- and evaporation-mediated 2D colloidal assemblies on fluid interfaces

Fluid interfaces exhibit remarkable capabilities and significant application prospects in fabricating twodimensional (2D) materials and colloidal assemblies. However, the efficient realization of the fluid-mediated self-assembly of colloidal particles has become challenging owing to the complex evolution of spatiotemporal processes and dynamic behaviors at fluid interfaces. In this study, we hypothesized that the superspreading of a volatile droplet directed the ultrafast self-assembly of colloidal particles on an insoluble fluid interface. To validate this hypothesis, employing high-speed and large-field microscopic observation experiments in tandem with theoretical analysis, the time evolution processes of droplet spreading, evaporation, dewetting, and particle assembly were captured, and the multi-scale dynamic behavior of volatile colloidal droplets on an immiscible liquid substrate was studied. Our findings revealed the power law of droplet spreading dynamics at the macroscale, evaporation-induced dewetting of the liquid film and aggregation of colloidal particles at the mesoscopic scale, and colloidal self-assembly under the action of capillary and DLVO forces at the microscopic scale. Moreover, we realized the ultrafast fabrication of 2D colloidal assemblies on liquid interfaces. This work presents a simple, robust, and efficient method for self-assembling and manufacturing 2D-ordered structures and materials based on a platform of fluid interfaces

Tunable Spreading and Shrinking on Photocontrolled Liquid Substrate

Droplets of n-hexadecane were observed to shrink under ultraviolet (365 nm) and spread under blue light (475 nm) irradiation on an aqueous solution of photosensitive surfactant AzoTAB. We demonstrate that the change of wettability of n-hexadecane droplet on the solution depends on the change of oil-water interface tension. According to the addition of ethanol into the substrate, the change of relative diameter Delta D/D exceeds 20%, much larger than the system without ethanol. With light-emitting diode (LED) light as a sole power source, without any other triggers, we provide a contactless and isothermal method to realize photocontrolled alternative spreading and shrinking of a droplet on a liquid surface, which provides a basis for a chromocapillary-based optical zoom liquid lens

Distributed Power Trading System Based on Blockchain Technology

The power trading system has the characteristics of nonlinearity, dynamics, and complexity. Part of the business data in the trading system needs to be exposed to numerous external business systems. The traditional centralized power trading model has some problems, such as low data security and trust crisis of regulators. Blockchain technology provides prominent ideas for solving these problems. Firstly, the improved AdaBoost algorithm is used to predict the supply and demand gap of power trading nodes. Secondly, based on the fact that the information on the blockchain is only open to the power supply side, a two-stage game model of asymmetric information between the power supply side and the power user is constructed to capture the price competition behavior between them in order to find the Nash equilibrium price in two stages. Finally, the US PJM market electricity market data are used to carry out an example analysis to verify the effectiveness of the algorithm and model