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The energy distribution of output electrons (EDOE) from a microchannel plate (MCP) is measured using electrons emitted by a vacuum photodiode excited by a 266 nm Ti-sapphire femtosecond laser. The photoelectrons emitted from the photocathode are focused on a specific location of the MCP by a magnetic lens. While exist an enough voltage difference between the two ends of MCP, the energy distribution curve of output electrons form MCP can be obtained by analyzing the data as function of the bias voltage applied to the charge collector. The result shows that the energy distribution curve obtained by this means consists of a sharp and a long tail when using pulse light source. The most probable electron energy (MPE) is 12.64 eV and the full width at half maximum (FWHM) of the energy distribution curve is about 29.23 eV while the applied voltage difference is 700 V in the experimental setup. The MPE is 10.63 eV and the FWHM of the energy distribution is 22.436 eV in simulation. The measured curve is consistent with the expectation from simulation.

In the two-dimensional Cartesian coordinate system, a transient electromagnetic forward algorithm of the magnetic moment in arbitrary direction is developed to simulate the electromagnetic response characteristics of the whole space geoelectric model. The magnetic moment ${\mathbf {M}}_{r}$ in arbitrary transmitting direction is decomposed into ${\mathbf {M}}_{x}$ and ${\mathbf {M}}_{y}$ . The transient electromagnetic fields excited by the magnetic moments ${\mathbf {M}}_{x}$ and ${\mathbf {M}}_{y}$ are forwarded separately, and then synthesized to obtain the electric field excited by the magnetic moment ${\mathbf {M}}_{r}$ . The time domain iteration’s results of the uniform whole space are compared with the analytical solutions to verify the correctness of algorithm. The comparison results show that the algorithm is reliable and can be used for whole space transient electromagnetic simulation in an arbitrary direction. The forward response of the magnetic moment in an arbitrary transmitting direction removes the shortcomings of the traditional two-dimensional whole space transient electromagnetic simulations where the magnetic moment can only be in the horizontal or vertical direction. The program code can be used for the forward response of other two-dimensional whole space geological mining models. It is of great significance to study the two-dimensional transient electromagnetic diffusion characteristics of different geological models by the sector sweeping method.

In this paper, a novel substrate integrated waveguide (SIW) filtenna with two controllable radiation nulls is proposed, which has the advantage of good radiation characteristics. Radiation nulls are generated by electric and magnetic mixed coupling structure and fundamental mode, respectively. And a quasi-elliptic characteristic can be obtained at the boresight gain direction. By changing the length of perturbation slot and the strength of electric coupling and magnetic coupling, the position of radiation nulls can be controlled independetly. Compared to conventional filtenna, the proposed SIW filtenna has no extra filtering circuit to increase the dimension and complexity. Two resonant modes in the passband can be excited through loading electric and magnetic mixed coupling structure in one SIW cavity. The measured results are in good agreement with simulated results. The good frequency selectivity and out-of–band rejection are achieved. The proposed antenna exhibits a maximum realized gain of 5.8 dBi at the operating bandwidth. The measured impedance bandwidth is from 9.44 GHz to 9.68 GHz and the cross-polarization levels are lower than -20 dB in both planes.

This paper proposed a novel hybrid-excited wound field synchronous machine (HE-WFSM) to efficiently use the field torque and reluctance torque. Meanwhile, an analytical method is utilized to achieve the torque-angle consistency principle, which allows the field torque and the reluctance torque to reach their maximum values at the same phase current angle. First, a novel HE-WFSM with two different rotor excitations is proposed. Second, the PMs and the field windings in the rotor are designed by an analytical method based on the magnetic equivalent circuit (MEC) to produce the same magnetic flux in the air gap to obtain the torque-angle consistency. Third, one practical HE-WFSM applied for a small power fan is designed by the analytical method as an example. Finally, all the performances of the proposed HE-WFSM are predicted by the finite element method (FEM), thereby verifying the improved torque characteristics.

We demonstrate graphene-on-diamond field effect transistor (FET) actions modulated by optically excited charge state of nitrogen-vacancy (NV) centers in diamond. Palladium (Pd) metal contacts on graphene serve as the source and the drain. Negative charge state NV- center in diamond serves as the gate with diamond being the gate dielectric and produces an electric field to enhance the hole concentration in the graphene channel. The conductivity of graphene varies with negative charge state NV- center, resulting in differential conductance. The negative gate bias is removed when a NV- center is converted to an NVo center. P-type graphene channel exhibits positive differential conductance under illumination by a blue (405 nm) laser beam while on the contrary negative differential conductance by a red (633 nm) laser beam. Furthermore, by simultaneous illumination of both blue and red laser beams, effects on differential conductance decrease according to the relative intensity of the two laser beams. Graphene FETs with wavelength dependent multiple optical inputs and one electrical output in response to the charge state of NV centers in diamond has been reported.

Resonant excitation analysis on asymmetrical lateral leakage of light in the finite zero-contrast grating (ZCG) mirror is demonstrated, and the size effect of the excited source is investigated. The dispersion equation of slab waveguide for the TM mode is proposed to evaluate the resonant condition of the ZCG mirror, and it is shown that the mirror effect of the infinite ZCG is resulted from the overlapping of order-mode resonance pairs. However, two leaky channels are excited in spectra of the finite ZCG mirror for the normal-incident Gaussian source, where bound states in the continuums (BICs) turn into quasi-BICs as the angular component is nonzero. The leaky channels are confined in the grating layer and the sublayer, and they are all transferred from the symmetrical mode to the asymmetrical mode along the lateral direction from the center of the ZCG. The asymmetrical loss of the lateral leakage of light relative to incidence direction, in principle, can break reflection reciprocity of the symmetrical system of the finite ZCG mirror. By changing the excited source from the grating side to the sublayer side, the lateral leakage of light of the finite ZCG mirror can be efficiently reduced.

In this paper, a slots-coupled omnidirectional circularly polarized (CP) cylindrical dielectric resonator antenna (DRA) is proposed. The TM $_{01 \delta }$ and TE $_{\mathrm {011+\delta }}$ modes of the cylindrical DRA are simultaneously excited by four printed slots placed at 45 degrees to the radial direction. Omnidirectional CP fields are obtained when the fields of the two modes have the same amplitude and 90 degrees phase difference. Compared with the traditional probe-fed method, the structure of the proposed slots-coupled DRA is very simple, without introducing any groove, patch, choke or shorting pins. For the demonstration, a slots-coupled omnidirectional CP cylindrical glass DRA is designed for 5.8-GHz WLAN application. It is found that the proposed DRA can provide an AR bandwidth of ~8% (5.62-6.09 GHz) and a gain of ~5.6 dBic, with a height of $\sim 0.127\lambda _{0}$ . This performance is competitive with other reported omnidirectional CP DRAs.

Based on the photoacoustic spectroscopy technology, this research designed a photoacoustic cell system for detecting gas concentration. By injecting a beam of periodically modulated light, the light reacts with the mixed gas. The gas molecules absorb the light and transition from the ground state to the excited state and then release heat. The periodically changing heat will generate periodically changing pressure, thereby generating sound waves. After receiving the sound wave through a microphone, the gas concentration can be calculated by analyzing the collected signal. This paper analyzes the principle of harmonic detection and analyzes the relationship between input thermal amplitude and sound pressure.

Based on the photoacoustic spectroscopy technology, this research designed a photoacoustic cell system for detecting gas concentration. By injecting a beam of periodically modulated light, the light reacts with the mixed gas. The gas molecules absorb the light and transition from the ground state to the excited state and then release heat. The periodically changing heat will generate periodically changing pressure, thereby generating sound waves. After receiving the sound wave through a microphone, the gas concentration can be calculated by analyzing the collected signal. This article analyzes the relationship between different gas concentration detection and amplitude output.

A semiconductor device, such as an InSb transducer, can be used for pressure gradient sensing. Temperature affects local dynamic diffusion current within an InSb transducer. Parameters such as mobility and diffusion coefficients depend on scattering, and the major scattering effects are also temperature dependent. In turn, electrical responses excited by acoustically driven band gap modulation are affected. The open-circuit voltage of an indium antimonide transducer subject to acoustic resonance is amplified 0.3 percent per Kelvin by an increase in temperature. Quantum effects on carrier transport and behavior also depend on temperature, so there are temperature limits in which quantum effects are minimal. At very low temperatures, the quantum effects and wave nature of carriers can play a significant role in carrier behavior and transport.

For the first time, RIN reduction in gain-switched quantum dot laser is demonstrated with an optical beam illumination to the excited state. It is also found that pulses having a width of 27–29 ps with a high peak power are generated under the noise.

For the first time, with an optical beam illumination, gain-switched short pulses with a width of 25–40 ps with a high peak power are generated owing to excited state transitions, and the change in the laser parameters does not affect the output pulses strongly.

The objective of this paper is to propose a new spectroscopic method for observing vacuum arc phenomena. Spectroscopic observation is an important method in the study of vacuum arcs. Using the spectroscopic method, one can obtain a lot of useful information, for example, the excited state of atoms and the temperature of arcs. To obtain spectral data, spectrometers and narrowband filters are mainly used. Spectrometers are usually equipped with a slit, thereby spatial information is limited to one-dimensional information along the slit. A narrow band filter enables to obtain two-dimensional image, but the wavelength is limited to a specific value of the filter. Since arcs have a spatial expansion, it is desirable to obtain two-dimensional spatial information, also in the case of spectroscopic observations. In astronomy, a method to obtain spectroscopic data of two-dimensional images such as nebula and galaxies is used. This method is referred to as Integral Field Spectroscopy (IFS) and is used to obtain the spectroscopic information of a two-dimensional image in a single exposure. An IFS system combined with a high-speed camera system can record the time variation of a two-dimensional arc image and its spectroscopic data. We named this method "Time-Resolved Integral Field Spectroscopy". A prototype was built and the feasibility of this method was verified by observing a real vacuum arc.

PIC MCC simulation results on the breakdown in the pulse discharge in helium at pressure of 100 Torr and voltage of U=3.25 kV are presented. The delay of the breakdown development is studied with different initial densities of plasma and excited helium atoms, which corresponds to various discharge operation frequencies. It is shown that for high concentration of excited atoms the photoemission determines the breakdown delay time. In opposite case of low excited atoms density, the ion-electron emission plays a key role in the breakdown development. The photoemission from the cathode is set with a flux of the photons with Doppler shift over the frequency. These photons are generated in reactions between exited atoms and fast atoms. A wide distribution of breakdown delay time was observed in different runs and analyzed.

We have developed live cell autofluorescence imaging system with DUV-SPR. We measured the intensity reflectance of the laser beam in the Kretschmann configuration for P and S-polarized light, and confirmed that the SPR was excited by P-polarized light. The autofluorescence of living HeLa cells was imaged using the excited DUV-SPR.

The plasmonic responses of gold nanoplates were investigated toward all-optical nano-memory. The simulation clarified that the “triangular” configuration was superior in the resonance peak characteristics, compared to the regular circular configuration.

We experimentally demonstrated the surface plasmon propagation of crystalline silver nanowire excited by fluorescence of quantum dots. The scattered light origin from SPR was observed at one end of nanowire when the linear-polarized excitation light was focused onto another end.

Localized surface plasmon resonance is generally excited by light. However, more localized excitation is expected to be achieved by electron beam irradiation. In this study, we irradiated metal nanoparticles with an electron beam using a scanning electron microscope and measured their optical responses.

Hybrid excited synchronous machines are getting used wider and have perspectives for being used in many spheres where there is a need in efficient machine with magnetic flux control ability, especially, while prices on permanent magnets are getting higher. Models of synchronous machines with hybrid excitation allows to simulate different operation modes itself and create more complex models including this type of machine. For accurate analysis of hybrid excitation synchronous motor and it`s drive control it is significant to have an accurate model. This paper deals with comparison of synchronous machine with hybrid excitation with non-sinusoidal and sinusoidal back-emf.

The existence of non-radiating sources with high reduction of far-field radiation and accumulation of electromagnetic field in the near-field zone is crucial for various branches of science from medical imaging to dark matter. Here a non-radiating electric source consisted of an ultra-high permittivity dielectric hollow disk excited by an electric point-like dipole antenna placed inside the disk is studied. We theoretically demonstrate that such a system supports anapole state with radiation suppression to the far-field. The radiation suppression is obtained by destructive interference between the point-like dipole antenna’s radiation and the hollow disk’s induced current.

We report modeling and experimental characterization results of the propagating photonic bound states in a silicon-on-insulator (SOI) metastructure. The photonic bound states in the metasurface can be excited by the interaction between the discrete resonant modes and the incident wave. The calculated dispersion diagram shows anticrossings with continuous spectral narrowing at surface normal- and oblique-incidence excitations. In the presentation, we will discuss the measured spatial and spectral responses of the reflected beam from the fabricated SOI metastructure.

We show that a homogeneous high-index dielectric sphere can exhibit an effective negative permeability. Specifically, we analytically demonstrate that a high-index dielectric can support Mie resonances, where the electromagnetic spatial distributions outside the sphere accurately reproduce the spatial profiles of magnetic localized surface plasmons, generally excited by negative permeability subwavelength particles.

Multibeam (MB) radiations of antenna arrays need effective beamforming networks (BFNs). This paper presents a fisheye lens-based BFN (FL-BFN) by parallel-plate sandwiched substrates. It implements the beam and antenna excitation ports on the half-circular circumference and straight-line boundaries. The rule to determine the positions of antenna elements is shown for easy design. The performance is validated by using it to excite a Vivaldi antenna array. Measurements over a prototype were performed to validate its feasibility with good agreements.

The interaction between light and plasmonic structures at the deep-nanometer scale, which is essentially governed by nonclassical effects, has been increasingly investigated by the hydrodynamic model. Several hydrodynamic models have been introduced, in order to describe the motion of the free electron gas in metals. In this work, by employing the hard wall hydrodynamic model (HW-HDM) and the quantum hydrodynamic model (Q-HDM), the nonlocal response of an isolated metallic nanoparticle, excited by a dipole emitter, is investigated. The analysis is performed for the local density of states of an emitter coupled with a spherical nanoparticle, which may be treated analytically. Both radial and tangential emitters are studied, while varying the emitter–nanoparticle separation, and the nanoparticle’s size and material. It is shown that HW-HDM and Q-HDM may generate striking spectral features, which do not arise within the classical approach.

For the first time gain-switched short pulse generation with a width of 25-40 ps from excited state is demonstrated applying an external optical Gaussian beam to the excited state of InAs-InP-(113)B quantum dot laser.

The plasma chemistry generated by an electron beam emitted from a Febetron pulsed-power generator operating in different background gases is being investigated spectroscopically. The generator located at the Naval Research Laboratory produces a peak voltage of 80 kV, peak current of 4 kA with a pulse width of 100 ns. Once formed, the electron beam passes through a thin anode followed by a thin pressure barrier into a volume filled with different background gases at pressures ranging from 1000 to 10 mtorr. The volume is filled with both molecular (nitrogen and air) and atomic gases (Ar) to study the behavior of the generated plasma in these different conditions. The present work focuses on analysis of the emission spectrum from the electron beam generated plasma; of particular interest are spectral lines from the near ultraviolet to the visible (300 nm to 600 nm). The temporal and spatial variation of excited species are studied to understand the characteristics of the plasma.

Particle-in-cell Monte Carlo collision (PIC/MCC) simulations are important for understanding low pressure low-temperature discharge dynamics, since no assumptions are needed to determine the electron energy distribution function. Benchmark work is needed to build a solid base in the correctness of PIC/MCC codes. In this work, the basic object-oriented plasma device PIC/MCC code (oopd1-v1) is strictly benchmarked against the well-established xpdp1 code over a wide range of pressures (0.03 - 15 Torr), and varying size of the blocking capacitor in the external circuit (5 – 10 5 nF). An excellent agreement between codes is obtained. By upgrading oopd1-v1, incorporating excited argon atoms, metastable and radiative Ar m , Ar r , and Ar(4p), their role in rf capacitive discharges, especially in the collisional regime, was explored. It is found that the presence of the metastable atoms Ar m enhances the plasma density by a factor of 3 - 5 at 1.6 Torr and even higher at pressure up to 5 Torr. The proportion of metastable pooling ionization and step-wise ionization as an ionization source increases with increasing pressure and becomes more important than direct electronneutral ionization at 5 – 15 Torr. Also. as the pressure is increased the ionization occurs near the plasma-sheath interfaces, with little ionization within the plasma bulk region.

This paper presents a high-performance coupled BAW/SAW resonator based on ScAlN/Aln thin film hetero acoustic layered (HAL) structure. The influences of the SAW propagation characteristics for different geometrical parameters and configurations are investigated. The SAWs excited in the proposed HAL structure exhibits excellent performance due to the combined advantages of the coupling of BAW and SAW and its energy confinement effect. The optimized Mo/ScAlN/AlN/Mo/SiO 2 /Si structure exhibits a strong piezoelectric coupling (K2) of 21% and a high phase velocity ( $V$ ) of 5100m/ $s$ . And, a Qr is 3548 and Qar is 1348 around the resonance frequency of 4.83GHz and the anti-resonance frequency of 5.32GHz respectively. The coupled BAW/SAW resonator with large K2, high $V$ and high $Q$ provides promising prospects for development of high frequency, broadband and low-loss filters for 5G application.

A cluster of impenetrable scatterers is excited by a point source located inside a penetrable scatterer. The conservation of energy and the energy transfer process for this problem are considered. Relations of the scattering cross section with the complex sound intensity in the exciting scatterer are derived. A connection between the energy densities in the cluster's exterior and the reactive acoustic intensity through the exciting scatterer is established.

The terahertz radiation associated with optical electron transitions involving donor states in GaAs/AlGaAs quantum wells is investigated under conditions of interband optical excitation. It has been shown that the near-infrared stimulated emission arising at high optical pumping levels as well as impurity compensation can substantially influence on the intensity and spectra of terahertz photoluminescence related to the optical transitions of electrons from the first electron subband and excited donor states to the ground donor states in quantum wells.

A novel physical mechanism is proposed which can actively manipulate coherent Smith-Purcell radiation[1] with graphene metasurface. The coherent radiation is generated from the resonantly coupling between waveguide modes excited by a moving electron beam and the diffraction waves by the graphene metafurface. Owing to the controllability of the electron beam and some properties of graphene, the fundamental properties of the coherent Smith-Purcell radiation can be actively manipulated by adjusting the chemical potential of graphene metasurface and electron beam velocity. This mechanism opens a way for dynamically tuning the radiation states of Smith-Purcell radiation.

In this work, we propose an angle-independent beam splitter based on spoof surface plasmon. Arbitrary incident waves can be divided in half, and scatter towards two specific and independent directions. The proposed beam splitter consists of the upper periodic metal cylinder and the metal grating below. The former is placed to modulate the incident wave and the spoof surface plasmon with the specified wave vector, and the latter is used to support the excited spoof surface plasmon. To verify the proposed functionalities, we design three beam splitters with different splitter angles and calculate their field distributions under the illumination of the same Gaussian beam. The ideal numerical results agree well with the theory.

Cd 1-x Mn x Te crystals exhibit a strong optical rectification and electro-optic effects. We present our studies on Cd 0.55 Mn 0.45 Te single crystals, operating as efficient emitters and detectors of THz radiation transients, when excited by femtosecond optical pulses.

Large HgTe nanocrystals are very attractive for THz technology since they possess strong intraband absorption at THz frequencies with hot carrier relaxation times of few picoseconds. Here, we demonstrate that large HgTe nanocrystals excited by femtosecond optical pulses emit coherent THz emission from 0.2 THz to 2.5 THz. Our study reveals the great potential of HgTe nanocrystals as an original scheme for coherent THz emission.

High-Q Fano resonance is excited from the hybridization of eigenmode and Rayleigh anomaly through introducing the tiny displacements in the designed terahertz metamaterial. The strength of Fano resonance can be controlled via varying the incident angle of terahertz waves. These results provide new insights into the design of terahertz devices.

We compared the forward and sideway THz wave emission from a flowing water line excited by subpicosecond laser pulses. The peak field of THz sideway emission from a 210 μm waterline in is about twice stronger than that in forward direction when a 2-inch focal length lens is used to focus the optical beam. This observation indicates that the length of plasma in water is much shorter than that in air, resulting in more THz emission to sideway. Moreover, we measured the THz emission energy from water line with different diameters. The forward THz emission decreases greatly when the diameter of the water line increases from 0.3 mm to 1.4 mm. However, the diameter shows a much less influence on the THz emission to sideway, especially for the large diameter of waterline. Our study shows that the sideway detection of THz wave from an ionized waterline is a better scheme to collect more THz signal. These observations are helpful to understand the THz generation from water and laser-induced ionization in water.

By employing ultrafast time-resolved optical pump terahertz (THz) probe spectroscopy, we report a comparative THz response on CVD grown topological insulator (TI) Sb 2 Te 3 under different temperatures. Both photo induced carrier dynamics attributed to the surface and bulk electrons are observed. The electron system undergoes an ultrafast excitation and relaxation and releases through intra-band and inter-band scattering.

Gallium oxide are a potential material for many applications and recent research showed its strong anisotropic properties in THz range. We applied THz-TDS and CW laser to study the excited carrier dynamics in our sample (Ga 2 O 3 , 010, Fe-doped). The results showed different response along two crystal axes. Along the a-axis we observed Drude response and conductivity are increasing with CW laser increasing, as the same as we expected. Our fitting results (by Drude model) of this direction also agreed with our expectation. Along the c-axis we observed non-Drude response and further experiments are needed.

We report on the ultrafast dynamics of spin reorientation using different excitation mechanisms in the orthoferrite Sm 0.7 Er 0.3 FeO 3 . First, intense few-cycle mid-infrared pulses tuned to optical phonon resonance are exploited to excite the lattice system. A finite time delay of the spin reorientation is observed at its initial dynamics, displaying the energy transfer between lattice and 4f system. In contrast, an instantaneous response is found when the f-f electronic transition of Sm3+ is resonantly excited. Our results indicate that 4f electronic pumping can alter the magnetic anisotropy due to the modification of 4f-3d exchange at femtosecond time scales, without involving lattice thermalization.

Herein we show the terahertz (THz) time-domain ellipsometry investigation of the InSb semiconductor. At room temperature, the carriers of InSb are thermally excited to the conduction band due to its narrow bandgap. We, nevertheless, show that THz ellipsometry can detect subtle differences between carrier densities of undoped and lightly doped InSb bulk semiconductors. The advantage of THz ellipsometry over other THz time-domain spectroscopy techniques is that it does not require reference measurements through an aperture or standard mirrors.

We observe third-harmonic generation (THG) and fifth-harmonic generation (FHG) of terahertz free-electron laser (FEL) pulses in Si:B at cryogenic temperatures. The intensities of the harmonics increase as a function of pulse energy following power laws with exponents of 4.2 and 6.2, respectively. We attribute the generation of the fifth harmonic mainly to the valence band non-parabolicity. The values of χ(3) and χ(5) increase with the density of mobile carriers, which are excited via impact ionization of the boron dopants under irradiation by the intense FEL pulses.

A layered spherical medium is excited by a number of external electric dipoles. Boundary-value problems for the involved individual and overall electromagnetic fields are formulated. The direct scattering problem is solved by a T-Matrix method. Explicit formulas for the far-field, the overall cross section and the total interaction cross sections are derived. Some preliminary numerical results on the variations of these cross sections are presented.

In this paper we introduce an analytical method to control the response of conformal metasurfaces with respect to an impinging plane wave as excitation source. We first develop and present the analytical framework in order to achieve a full control over the current distribution within the metasurface. Then, in order to prove the theoretical model, we design a test-case through a numerical solver, consisting in a curved magnetic metasurface excited by a plane wave. The obtained numerical results are in excellent agreement with the theory, confirming the validity of the proposed approach. In this way, an accurate and effective control over conformal magnetic metasurfaces can be accomplished, extending the possible technological applications with respect to the traditional planar configuration.

Magnetoelectric (ME) magnetic field sensors are an aspiring sensor type for the accurate measurement of biomagnetic fields in applications such as magnetocardiography or placing of deep-brain stimulation electrodes. Their design allows measurement of magnetic fields in the low pT-range while offering unique benefits such as unshielded operation and no requirement of additional heating or cooling [1] . In previous work, we demonstrated that cantilever-type ME sensors of strain-coupled magnetostrictive and piezoelectric layers exhibit a strongly position-dependent behavior when excited by inhomogeneous magnetic fields [2] . Here, we investigate in a theoretical study a sensor with reduced magnetostrictive layer size with the aim to increase the spatial resolution.

Static and ultrafast optical characterization of gold(I) alkynyls having 2,7-disubstituted fluorenyl moieties are described herein. Capping phosphine or N-heterocyclic carbene ligands on Au control rates of radiative and nonradiative decay, and of intersystem crossing. Density-functional theory calculations indicate that luminescence originates from the alkynyl ligands.

We investigate the scattering properties of a paired periodic array of silver-dielectric metasurfaces. We report Fano resonances and Rabi splitting in the spectral response of the scattering parameters. We show that tuning the refractive index of the dielectric scatterer defines whether identical or mismatched resonances are excited in the array.

This work presents an analysis of the optical properties of transition metal adatom-graphene quantum dot complexes (TM-GQDs). TM-GQDs with five metals (Cr, Mo, W, Pd, and Pt) and pristine GQDs were investigated to explore the possibility of engineering the optical characteristics. By Density Functional Theory and Time-Dependent Density Functional Theory, excited energy states and absorption spectra were analyzed. As a function of graphene quantum dot sizes and TMs, significant changes in HOMO-LUMO levels and optical transition energies were observed. The HOMO-LUMO gaps and energy levels in the visible range clearly indicate the adatom induced energy level shifts, showing smaller energy gaps in TM-GQDs than the pristine GQDs. The calculated THz absorption spectra show strong dependency on the size and adatom mass of TM-GQDs. The tunable optical properties of the TM-GQDs can be utilized as optical sources for future display applications.

A design of self-diplexing cylindrical dielectric resonator antenna (DRA) is presented in this paper. The DRA is based on ceramic material. The $\text{HEM}_{11\delta}$ and $\text{TM}_{02\delta}$ modes of the cylindrical DRA are excited by differential feeding and a metal probe respectively. A stub is adopted to suppress spurious modes of HEM and improve the isolation of the two input ports. The results show that, within two frequency bands 2.73-3.05 GHz and 6.19-6.52 GHz, the proposed antenna achieves good impedance matching ( $\vert S_{11}\vert ), and isolation (>26 dB). The proposed self-diplexing DRA could be appllied in modern wireless communication.

The electric field levels established at various points within a modeled rocket fairing under different excitations are measured. Both interior sources placed within different fairing sub cavities and exterior excitation was used. The effect of the addition of different absorbers on the electric field level in different sub cavities was investigated as well. The shielding effectiveness of the fairing within the different fairing sub cavities was considered. The relation between the total surface of absorber and the electric field level studied. In addition, the electric field level excited inside the fairing under external illumination was numerically simulated. The laboratory measurements were verified through comparison with the simulation results.

We report on an observation of the 1S-2S transition in atomic hydrogen using an ultraviolet mode-locked laser. The 243 nm femtosecond laser is produced through second-harmonic generation and sum-frequency generation from a Ti:sapphire mode-locked laser. After cooling the atoms to 7.8 K, a florescence signal with 800 kHz linewidth is observed. Our scheme provides a potential approach to realize the high-precision frequency standard based on hydrogen transition.