Catálogo de publicaciones - revistas

<jats:p>The zinc oxide (ZnO) nanoparticles (NPs) sensors were prepared <jats:italic>in-situ</jats:italic> on the gas-sensing electrodes by a one-step simple sol-gel method for the detection of hydrogen sulfide (H<jats:sub>2</jats:sub>S) gas. The sphere-like ZnO NPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), energy dispersive x-ray analysis (EDX), and their H<jats:sub>2</jats:sub>S sensing performance were measured at room temperature. Testing results indicate that the ZnO NPs exhibit excellent response to H<jats:sub>2</jats:sub>S gas at room temperature. The response value of the optimal sample to 750 ppb H<jats:sub>2</jats:sub>S is 73.3%, the detection limit reaches to 30 ppb, and the response value is 7.5%. Furthermore, the effects of the calcining time and thickness of the film on the gas-sensing performance were investigated. Both calcining time and film thickness show a negative correlation with the H<jats:sub>2</jats:sub>S sensing performance. The corresponding reaction mechanism of H<jats:sub>2</jats:sub>S detection was also discussed.</jats:p>

<jats:p>This review summarizes the requirement of low temperature conditions in existing experimental approaches to quantum computation and quantum simulation.</jats:p>

<jats:p>The multipartite Greenberger–Horne–Zeilinger (GHZ) states play an important role in large-scale quantum information processing. We utilize the polychromatic driving fields and the engineered spontaneous emissions of Rydberg states to dissipatively drive three- and four-partite neutral atom systems into the steady GHZ states, at the presence of the next-nearest neighbor interaction of excited Rydberg states. Furthermore, the introduction of quantum Lyapunov control can help us optimize the dissipative dynamics of the system so as to shorten the convergence time of the target state, improve the robustness against the spontaneous radiations of the excited Rydberg states, and release the limiting condition for the strengths of the polychromatic driving fields. Under the feasible experimental conditions, the fidelities of three- and four-partite GHZ states can be stabilized at 99.24 % and 98.76 %, respectively.</jats:p>

<jats:p>We present a cooling scheme with a tripod configuration atomic ensemble trapped in an optomechanical cavity. With the employment of two different quantum interference processes, our scheme illustrates that it is possible to cool a resonator to its ground state in the strong cavity–atom coupling regime. Moreover, with the assistance of one additional energy level, our scheme takes a larger cooling rate to realize the ground state cooling. In addition, this scheme is a feasible candidate for experimental applications.</jats:p>

<jats:p>We study the abruptly autofocusing and autodefocusing properties of the circular Airy Gaussian vortex (CAiGV) beams in strongly nonlocal nonlinear medium for the first time through numerical simulations. The magnitude of topological charges and the position of the vortex could change not only the light spot pattern but also the intensity contrast. Meanwhile, we can change the position of the autofocusing and autodefocusing planes by changing the parameter of the incident beam. Furthermore, we can control the peak intensity contrast through choosing properly the truncation factor. As for the radiation force, we study the gradient and the scattering forces of CAiGV beams on Rayleigh dielectric sphere. Our analyses demonstrate that the radiation force can be enhanced by choosing proper parameters of CAiGV beams.</jats:p>

<jats:p>We theoretically investigate the effects of different electronic states as the initial state on the vortex patterns in photoelectron momentum distributions (PMDs) from numerical solutions of the two-dimensional (2D) time-dependent Schrödinger equation (TDSE) of He<jats:sup>+</jats:sup> with a pair of counter-rotating circularly polarized attosecond pulses. It is found that the number of spiral arms in vortex patterns is equal to the number of the absorbed photons when the initial state is the ground state. However, the number of spiral arms in vortex patterns is always two more than the number of the absorbed photons when the initial state is the excited state. This sensitivity is attributed to the initial electron density distribution. In addition, we have demonstrated the PMDs for different initial electronic states with the same wavelengths and analyzed their corresponding physical mechanisms. It is illustrated that the method presented can be employed to effectively control the distribution of the electron vortices.</jats:p>

<jats:p>A high-sensitive terahertz detector operating at room temperature was demonstrated based on parametric up-conversion. A nanosecond 1064-nm Nd:YAG laser was used to pump the parametric up-conversion detector and the up-conversion from terahertz wave to NIR laser was realized in a lithium niobate crystal. The minimum detectable terahertz energy of 9 pJ was realized with the detection dynamic range of 54 dB, which was three orders of magnitude higher than that of commercial Golay cell. The detectable terahertz frequency range of the detection system was 0.90 Thz–1.83 THz. Besides, the effects of pump energy and effective gain length on the detection sensitivity were studied in experiment. The results showed that higher pump energy and longer effective gain length are helpful for improving the detection sensitivity of parametric up-conversion detector.</jats:p>

<jats:p>We design and demonstrate a one-dimensional grating coupler with a low polarization-dependent loss (PDL) for large spatial light spots. Based on current fabrication conditions, we first utilize genetic algorithms to find the optimal grating structure including the distributions of duty and periods, making the effective refractive index of transverse electric mode the same as that of transverse magnetic mode. The designed grating coupler is fabricated on the common silicon-on-insulator platform and the PDL is measured to be within 0.41 dB covering the C-band.</jats:p>

<jats:p>A novel complementary grating structure is proposed for plasmonic refractive index sensing due to its strong resonance at near-infrared wavelength. The reflection spectra and the electric field distributions are obtained via the finite-difference time-domain method. Numerical simulation results show that multiple surface plasmon resonance modes can be excited in this novel structure. Subsequently, one of the resonance modes shows appreciable potential in refractive index sensing due to its wide range of action with the environment of the analyte. After optimizing the grating geometric variables of the structure, the designed structure shows the stable sensing performance with a high refractive index sensitivity of 1642 nm per refractive index unit (nm/RIU) and the figure of merit of 409 RIU<jats:sup>−1</jats:sup>. The promising simulation results indicate that such a sensor has a broad application prospect in biochemistry.</jats:p>

<jats:p>The broadband absorption enhancement effect in ultrathin molybdenum disulfide (MoS<jats:sub>2</jats:sub>) films is investigated. It is achieved by inserting the MoS<jats:sub>2</jats:sub> film between a dielectric film and a one-dimensional silver grating backed with a silver mirror. The broadband absorption enhancement in the visible region is achieved, which exhibits large integrated absorption and short-circuit current density for solar energy under normal incidence. The optical properties of the proposed absorber are found to be superior to those of a reference planar structure, which makes the proposed structure advantageous for practical photovoltaic application. Moreover, the integrated absorption and short-circuit current density can be maintained high for a wide range of incident angles. A qualitative understanding of such broadband absorption enhancement effect is examined by illustrating the electromagnetic field distribution at some selected wavelengths. The results pave the way for developing high-performance optoelectronic devices, such as solar cells, photodetectors, and modulators.</jats:p>