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Retro-reflected wave power of cat-eye target is an important factor for active laser detection system, which can evaluate high or low cat-eye effect of photoelectrical device. Theoretical and experimental results show that retro-reflected wave power will rapidly decline with defocusing distance increases and the decline more notable in negative defocusing condition.

Coherent storage of optical image in a coherently-driven medium is a promising method with possible applications in many fields. In this work, we experimentally report a controllable spatial-frequency routing of image via atomic spin coherence in a solid-state medium driven by electromagnetically induced transparency (EIT). Under the EIT-based light-storage regime, a transverse spatial image carried by the probe field is stored into atomic spin coherence. By manipulating the frequency and spatial propagation direction of the read control field, the stored image is transferred into a new spatial-frequency channel. When two read control fields are used to retrieve the stored information, the image information is converted into a superposition of two spatial-frequency modes. Through this technique, the image is manipulated coherently and all-optically in a controlled fashion.

The hydrodynamics in a gas-solid draft tube-lifted air-loop reactor (GSALR) was investigated systematically using experimental measurements. To demonstrate the gas-solid flow pattern, the upward particle velocity, downward particle velocity and time-averaged particle velocity in four regions of the GSALR were measured by optical fiber probe under different superficial gas velocities. The experimental results show that the downward particle velocity distributes uniformly along the radius in the four regions, but the radial distributions of upward particle velocity and time-averaged particle velocity are core-annulus or heterogeneous structure in the three regions (distributor affect region, draft tube, gas-solid diffluence region), which have the common feature of aggregative fluidization occurred in normal fluidized beds. The operating condition such as superficial gas velocity in draft tube has different effects on the radial distributions of upward particle velocity, downward particle velocity and time-averaged particle velocity in each region. Analysis of the distributions of upward particle velocity, downward particle velocity and time-averaged particle velocity leads to suggestions regarding optimization of the design and provides further theoretical basis for industry application of GSALR.

Unlike usual astrophysical sources of gravitational wave (GW), strong electromagnetic (EM) oscillation systems, high-energy particle beams, solar plasma and crystal arrays are able to produce GWs of extremely high-frequency. Their frequencies may reach up to 108 Hz or higher, but the corresponding amplitude orders are only 10-33 - 10-40. We review the possibility of EM detection for the above GWs. In addition, the maximal signal of high-frequency relic GWs, recently expected by quintessential inflationary models, may be firmly localized in the GHz region. We estimate perturbative effects of the relic GWs to the EM detection systems, and show that the effects can possibly provide a new scheme for the EM detection of the relic GW in the GHz window.

We consider the resonant response of a Gaussian beam passing through a static magnetic field to a high-frequency relic gravitational wave (GW). It is found that under the synchroresonance condition, the first-order perturbative electromagnetic energy fluxes will contain a ``left circular wave'' and a ``right circular wave'' around the symmetrical axis of the Gaussian beam, but the perturbative effects produced by the + and × polarization of the GW have a different physical behaviour. For the high-frequency relic GW with νg = 1010 Hz, h = 10-30, recently expected by the quintessential inflationary models, the corresponding perturbative photon flux passing through the region 10-2 m2 would be expected to be 104 s-1. This is the largest perturbative photon flux we have recently analysed and estimated using the typical laboratory parameters.

Concrete forms of resonant response (ER) for a strong electromagnetic (EM) wave beam (photon flux) propagating in a static magnetic field to a standing gravitational wave (gravitons) are given, and the corresponding perturbation solutions and resonant conditions are obtained. It is found that perturbed EM fields (PEMFs) contain three new components with frequencies | ω g ± ω e | and ω g , respectively. In the case of ω e >> ω g , the PEMFs are manifested as the EM wave beams with frequency ω e and a standing EM wave withωg. The former and the background EM wave beam (BEMWB) have the same propagating direction, while in the case of ω g >> ω e , all PEMFs are expressed as the standing EM waves with frequency ω g . The resonant response occurs in two cases of ω e = 1/2 ω g and ω e = ω g only. Then not only the first order perturbed energy fluxes (PEFs) propagating in the same and opposite directions of the BEMWB can be generated, but also radial and tangential PEFs which are perpendicular to the above directions can be produced. This effect might provide a new way for the EM detection of the gravitational waves (GWs). Moreover, the possible schemes of displaying perturbed effects induced by the standing GW with h =10 -33 −10 -35 and λ g =0.1 m at the level of the single photon avalanche and in a typicla laboratory dimension are reviewed.

Total Routhian Surface (TRS) calculations have been performed for even-even nuclei along proton drip line to study nuclear ground-state deformations, as well as the odd proton nuclei Ho and Tm isotopes. The drip line nuclei show the expected shape transition with the shell e?ects. Ground-state shape changes from prolate to oblate at 143Ho and 145Tm in these two isotopes, which is due to the γ instability around N =76.

The Newtonian gravitational constantG is determined by means of the swing time method at the Cave Laboratory of Center for Gravitational Experiment of Huazhong University of Science and Technology. The result value ofG is (6.669 0 ± 0.001 6) × 10-11 m3·kg-1·s-2, which is consistent with the CODATA value of G obtained by Cohen and Taylor in 3σ.

A phenomenological study on the fitting method in real time has been done, and the method was applied to process and analyze the extensive data of a long period torsion pendulum used to determine Newtonian gravitational constant G. The result shows that the fitting method in real time is effective to determine the period of a torsion pendulum with a relative precision of 10-5 orders.

Starting with the diagonal spacetime metric tensor, the Einstein gravitational field equation is solved, and a set of exact (3 + 1) dimensional cylindrically symmetric wave solutions with two arbitrary functions are found. In these solutions all nonvanishing components of spacetime metric tensor are varying with the same propagating factor (ct-z) while the waves are travelling along z axis. The physical picture and the condition of positive energy density of the wave solutions are discussed.

By using the general expressions of energy-momentum pseudo-tensor of the cylindrical gravitational waves (GW) given by Rosen and Virbhadra in Cartesian coordinates, the concrete forms of energy density and radiative energy flux of the pulse cylindrical GW are obtained. Their physical properties, suitable range and asymptotic behaviour are considered. It is found that: For the region in which space radial coordinates to origin are greater than the pulse width of the pulse cylindrical GW, the energy density and radiative energy flux of the outward travelling pulse cylindrical GW propagating along a light-cone are positive definite. However, for the region in which the space radial coordinates are less than the pulse width, there is no guarantee for the positive definite property of the radiative energy flux of the outward travelling wave. Moreover, we show that the asymptotic behaviour of the energy and energy flux densities of the pulse cylindrical GW and that of the Riemann curvature tensor have good self-consistancy in space-like, time-like and null infinity regions.

Starting with the Einstein equation of weak gravitational field, a new scheme of generating high frequency gravitational wave by composite toroidal electromagnetic resonant system is discussed. The system is a composite toroidal electromagnetic resonant cavity consisting of a vacuum and a dielectric regions. In the focal region of the cavity under the condition of allowable ohmic losses in the cavity walls, the amplitude of the standing gravitational wave is almost two orders of magnitude higher than that in usual cavity with the same volume. A concrete numerical calculation shows that a composite toroidal electromagnetic resonant system with a volume 2 × 108 cm3 could generate the standing gravitational wave with an amplitude h = 10-33, wavelength λg = 40 cm in its focal region. This is comparable to the typical order of magnitude of several astrophysical sources, and it would be displayed by electromagnetic detection due to very high frequency.

Perturbed effect of high-frequency gravitational radiation produced by microwave electromagnetic (EM) cavity on static detecting EM field is investigated, and corresponding perturbation solutions have been given. It is found that the gravitational wave (GW) beam propagating along symmetric axis of the cavity is purely +type polarized in transverse traceless coordinate system, and it can make the static EM field generate a cumulative perturbed effect which is proportional to the time. For the gravitational radiation wave beams propagating along other directions, they are usually mixed radiation of + and × type polarization. Quality factor of the cavity plays a key role in interaction strength of the GW with the detecting EM field.

Coherent resonant conditions of a strong electromagnetic (EM) wave beam propagating in a static magnetic field to a standing gravitational wave (GW) are given. It is found that under the resonant conditions not only first-order perturbed energy fluxes (PEFs) propagating along the same and opposite directions to the background EM wave beam can be generated, but also radial and tangential PEFs which are perpendicular to the above directions can be produced. Such results might provide a new way to display the resonant response induced by the standing GW with h = 10-35 and λg = 0.1m at the level of the single photon avalanche effect.

We experimentally demonstrate multiple frequency conversion via atomic spin coherence of storing a light pulse in a doped solid. The essence of this multiple frequency conversion is four-wave mixing based on stored atomic spin coherence. Through electromagnetically induced transparency, an input probe pulse is stored into atomic spin coherence by modulating the intensity of the control field. By using two different control fields to interact with the coherently prepared medium, the stored atomic spin coherence can be transformed into three different information channels. Multiple frequency conversion is implemented efficiently by manipulating the spectra of the control fields to scatter atomic spin coherence. This multiple frequency conversion is expected to have potential applications in information processing and communication network.

Electrodynamical response (ER) to the high frequency standing gravitational wave (GW) of a composite toroidal electromagnetic resonant system is investigated, corresponding perturbation solutions are given, the advantages and shortcomings of electromagnetic detection to the standing GW by means of a static magnetic field and superconducting resonant cavity are compared. A concrete numerical calculation shows that under the reasonable states of the present technology, the ER to the standing GW can probably be displayed at the level of the single photon avalanche effect.

A set of exact (3+1)-dimensional cylindrically symmetric 2-soliton solutions with three arbitrary functions to the Einstein gravitational field equation is found. Their physical properties, such as nontriviality, propagation and positive definiteness of energy density, are discussed.

Maximal signal and peak of high-frequency relic gravitational waves (GW's), recently expected by quintessential inflationary models, may be firmly localized in the GHz region, the energy density of the relic gravitons in critical units (i.e., $ h_0^2 \Omega_{GW}$) is of the order $10^{-6}$, roughly eight orders of magnitude larger than in ordinary inflationary models. This is just right best frequency band of the electromagnetic (EM) response to the high-frequency GW's in smaller EM detecting systems. We consider the EM response of a Gaussian beam passing through a static magnetic field to a high-frequency relic GW. It is found that under the synchroresonance condition, the first-order perturbative EM power fluxes will contain "left circular wave" and "right circular wave" around the symmetrical axis of the Gaussian beam, but the perturbative effects produced by the states of + polarization and $\times$ polarization of the relic GW have different properties, and the perturbations on behavior are obviously different from that of the background EM fields in the local regions. For the high-frequency relic GW with the typical parameters $ \nu_g = 10^{10}Hz$, $ h = 10^{- 30} $ in the quintessential inflationary models, the corresponding perturbative photon flux passing through the region $ 10^{- 2} m^{2} $ would be expected to be $ 10^{3}s^{-1} $. This is largest perturbative photon flux we recently analyzed and estimated using the typical laboratory parameters. In addition, we also discuss geometrical phase shift generated by the high-frequency relic GW in the Gaussian beam and estimate possible physical effects., Comment: 36 pages, 5 figures

We experimentally study the controllable generation of a beating signal using stored light pulses based on electromagnetically induced transparency (EIT) in a solid medium. The beating signal relies on an asymmetric procedure of light storage and retrieval. After storing the probe pulse into the spin coherence under the EIT condition, two-color control fields with opposite detunings instead of the initial control field are used to scatter the stored spin coherence. The controllable beating signal is generated due to alternative constructive and destructive interferences in the retrieved signal intensities. The beating of the two-color control fields is mapped into the beating of weak probe fields by using atomic spin coherence. This beating signal will be important in precise atomic spectroscopy and fast quantum limited measurements.

The Newtonian gravitational constant G is determined by means of a high-Q torsion pendulum and the time-of-swing method, in which the period of the pendulum is altered by the presence of two 6.25-kg stainless steel cylinders. The nonlinear fitting method is used to extract the frequencies from the angle-time data of the pendulum. The resulting value of G is $(6.6699\ifmmode\pm\else\textpm\fi{}0.0007)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}{\mathrm{m}}^{3}{\mathrm{}\mathrm{kg}}^{\mathrm{\ensuremath{-}}1}{\mathrm{}\mathrm{s}}^{\mathrm{\ensuremath{-}}2}.$

A new ultra-low frequency passive vertical vibration isolation system is constructed by connecting the torsion spring isolator with a reverse pendulum. The theoretical analysis shows that the new system can achieve a much longer resonant period and have a smaller size than the current torsion spring isolators with the same geometric parameters.

We study the generation and evolution of continuous-variable entanglement in a holographic laser. The two-level atomic medium is trapped in a ring cavity, and couples with two counter-propagating modes. By simulating the dynamics of the system, our numerical results show that the two-mode continuous variable (CV) entanglement can be realized in the present system even in the presence of cavity loss. This investigation provides a research clue for realizing CV entanglement in a two-level atomic medium, which is simpler than the previous works.

Modulation on electromagnetic waves with angle frequency ωe,travelling around a circular waveguide by high-frequency plane gravitational waves with angle frequency ωg,incident perpendicularly to the plane,where the waveguide is located,is discussed.Results present that in the vicinity of symmetric plane,perpendicular to the travelling direction of gravitational waves, of the waveguide,energy flux density of electromagnetic waves,generally will be added by three new components with angle frequencies(2ωe±ωg)and ωg,respectively.In the case as ωg》ωe,ratio-modulation of amplitude of energy flux density is as large as h0, the dimensionless amplitude of the gravitational wave,in order.Specially,when for ωg,ωe and ω0,the cyclical angle frequency of electromagnetic waves around the waveguide, ωg=2ωe》ω0 is satisfied,energy flux density will be greater than h0 in order because of some mechanism,similar to resonance.The results don't vanish when these parameters have a small change.It is very important to detect the very weak signals of gravitational waves.

The effect of gravitational waves (GW) on phonon in axisymmectic non-uniform elastic medium is analysed by means of the complex coordinate in Serebryany's complex space. and expression of diving force produced by the GW and corresponding phonon soluitons are given. In our solution forms. they are shown that the GW propagating along symmetric axial direction generates only perturbation to radial and tangential components of the phonon fields. while the GW propagating along direction perpendicular to the symmetric axis generates perturbation to all components of the phonon fields. i.e., radial, tangential and axial components. The strength of pertur-bation depends on concrete form of radial distribution function of shear modulus and the GW's amplitude. Moreover, above results are compared with the GW's perturbing effect in topological phonon space with the spiral dislocation.

Starting with the Einstein-Maxwell equations of weak gravitational field, we discussed the interaction between narrow wave beam-type high frequency gravitational radiation of crystal space array and electromagnetic fields. The perturbed solutions have been obtained. By our calculation, it is shown that this gravitational wave beam with optimal radiation direction is purely + type polarized in TT coordinate system, and it can make electromagnetic wave, which has the same frequency, to generate perturbed effects of frequency doubling, make static electromagnetic fields to generate cumulative effect linear in time. For the gravitational radiation wave beam with an arbitrary direction, it is also purely+type polarized in the plane perpendicular to the gravitational wave vector. Under the condition of high frequency radiation and laboratory's typical size, difference between TT coordinate and Fermi coordinate systems can be neglected.

Starting from calculating the directivity pattern of bar-shaped gravitational wave antenna, the relation of position between gravitational waves detectors and source is discussed in this paper. Further, the methods, which is used to determine the position of gravitational wave source, based on the data of coincident experiments, and the position of continuous gravitational wave source, based on the data of single gravitational wave antenna, are obtained. These results are also applicable for other types of one-dimentional gravitational wave detector. Once the sensitivity of the gravitational wave detector reaches the level, enough to determine the intensity of gravitational wave, the results presented in this paper will undoubtedly be useful for gravitational wave astronomy in the future.

The results of coincidence experiment which was carried out in the whole month of April, 1985 by two gravitational wave detectors in stanford and in Guangzhou are presented. It is found that up to sensitivity of h 10-16 the number of coincident events did not excess the number expected statistically.