Ellagic acid is a polyphenol found in many species of plants. It plays an impotent role in inhibiting proliferation and inducing apoptosis of cancer cell. The ellagic acid also has the effect of antioxidation and radioresistance. It was used in a lot of medicine and health products. Terahertz time-domain spectroscopy (THz-TDS) is a new coherent spectral technique. The spectral characteristics of ellagic acid in the range of 0.2~2.4 THz were measured by THz-TDS. The vibration absorption spectrum of the single molecule between 0.2 and 2.4 THz is simulated based on the density functional theory (DFT). It is found that the ellgic acid has the spectral response to THz radiations in this frequency region, and it shows abnormal dispersion and absorption peaks at 0.44 THz, 0.73 THz, 0.99 THz, 1.26 THz, 1.58 THz, 1.87 THz and 2.19 THz.

Some new solutions of the first kind of elliptic equation and formula of nonlinear superposition of the solutions are given. Combing the solutions with function transformation to construct Jacobi-like elliptic function exact solutions, a number of soliton-like solutions and triangular solutions of (3+1)-dimensional Zakharov-Kuznetsov equation with variable coefficients are given with the help of symbolic computation system Mathematica.

A compact high-power diode laser system was demonstrated and reported. Weak laser beam of a distributed feedback laser was successfully injected into a tapered chip amplifier, from which more than 700 mW laser power was output and a continuous tuning range of 1 nm was achieved. The laser system has a compact structure and stable laser intensity, and it is convenient to operate. It can be used in laser cooling and trapping of neutral atoms, ultracold quantum gases, quantum information, atomic frequency standards, and relative experiments in space.

Using density matrix eqution, the absorption and dispersion properties of a Λ-type four-level system driven by coherent fields are investigated. The result obtained by means of numerical method indicates that by adjusting the intensity of Rabi frequencies of the coherent field in the steady state, three, double or single electromagnetically induced transparency (EIT) can appear explicitly in this system. And the explanations of these phenomena are given by using the dressed states. In the three EIT, the location of transparent windows can be manipulated by controlling the detuning of the driving field. What’s more, it is also found that the medium shows a large refractive index at each transparency window, and the group velocity of the probe laser can be enhanced.

Quantum circuits are the tools of realizing the unitary evolution of quantum state, and they are mainly made up of one-bit and two-bit quantum gates. Barenco proposed a method for constructing n-bit quantum gate by using basic two-bit quantum gates in 1995. Zhang proposed the improved method for constructing n-bit quantum gate by using basic two-bit quantum gates in 2001. The method for constructing n-bit quantum gate by using basic two-bit quantum gates is proposed by improving the two methods mentioned. The scheme is more simple and easier to implement and the incorrect conclusion by Zhang is amended.

By virtue of the linear quantum transformation theory(LQTT), a general formula is obtained, which calculate the quantum fluctuations for bipartite entangled state of continuous variables in Fock space. Moreover, the squeezed properties of the entangled state are discussed. The relations between the state parameters are depicted by means of the linear fitting, when the degree of the fluctuation and entanglement entropy reach the extremum. When the entangled state is maximally entangled, the results show that the squeezed degree is also maximal. In addition, the changing relationship between the quantum fluctuations and the quantum entanglement is acquired. The derived formula are used to calculate the fluctuation of the common two-mode squeezed vacuum state and the two-mode one-sided squeezed vacuum state as examples.

In the practical distribution process of quantum key, the transmission loss and efficiency of detectors have a direct impact on the efficiency of key generation. The quantum identity authentication requires both communication sides to ensure the integrity of the authentication information. Considering the problems above, a quantum identity authentication protocol based on photon polarization rotation is proposed, in which repetition coding is used to solve the problem of transmission loss. In order to guarantee the security of protocol, random states are inserted into the adjacencies of the useful authentication quantum states. Security analysis shows that the protocol can successfully resist the intercept-resent attack and beam-splitting attack. Furthermore, a useful authentication system practicable under present technical conditions is designed. It is helpful in applications that transmission loss and detection efficiency are taken into consideration.

With a five-particle entanglement GHZ state as the quantum channel, a quantum secret sharing scheme is proposed, which put through the three-particle teleportation in order to realize the three-quantum secret sharing. The safety of the scheme is analyzed. The scheme makes full use of five particles’ relationship of the GHZ-state. It is found that a Bell-basis measurement, three single particle measurement and corresponding unitary transformation are required. Compared with the pertinent literature, it enhances the quantum transmission without increasing the number of particles, and forms a theoretical basis for transmitting more quanta in quantum secret sharing.

The two-body thermal entanglement and mixture in a three-spin spin chain in thermal equilibrium state are investigated, and the effects of the temperature and magnetic field on the entanglement and mixture are discussed. It is found that, in the ground state, an important class of states, maximally entangled mixed states, can be generated by controlling magnetic field, which provide a new way to generate maximally entangled mixed states and control entanglement. Further, the spin chain in the thermal equilibrium is used as a quantum channel for quantum communication. The effects of temperature and magnetic field on fidelity are discussed. It is shown that the temperature and magnetic field have vast effects on the fidelity. The relation between fidelity and two-body thermal entanglement is given, which shows that more amount of entanglement does not means higher fidelity.

The quantum entanglement of two entangled atoms interacting with the squeezed coherent state is studied by means of full quantum theory. The influences of coherent amplitude factor, squeezing factor, ratio of two coupling coefficients on the entanglement property are discussed. The results show that two atoms entanglement evolution property is opposed to atom-field entanglement evolution property when the coherent amplitude factor was zero or small. The interaction of the atoms and field weakens the entanglement degree of atom-atom. With increasing coherent amplitude factor or decreasing squeezing factor of light, the time of two atoms staying in the steady entangled state becomes longer. The increase of the coherent amplitude factor or the decrease of squeezing factor of light lead to the increase of atom-atom entanglement degree while the decrease of atoms-field entanglement degree. Moreover, the two-atom quantum state stays in the maximum entangled state when the atomic dipole-dipole coupling coefficient is large enough.

For a system composed of a cavity with Kerr medium, a movable mirror (treated as a quantum harmonic oscillator with frequency ωm and a single mode field in the cavity, the time evolution operator and its transformation of the system are given. Time evolution of the system state is obtained with full quantum theory. State of the cavity field at the time of the mirror back to its original state is discussed, and a variety of multicomponent Schr?dinger cat states which are different from those in the published literature are obtained, which is significant for the investigation of the nature and applications of the Schr?dinger cat states.

Considering that three two-level atoms A, B and C were initially prepared in W or GHZ entangled state and two of them, A and B, interacted resonantly with coherent state field, after cavity QED evolution, Bell-basis measurement was performed on the two atoms inside cavity, through modulating the intensity of the coherent field and the strength of dipole-dipole interaction between atoms, one can controlled the evolution of atom’s occupancy of atom C outside cavity. The results show that the influence on the evolution properties of occupancy of atom C outside cavity is different under selecting different initial state and carrying out different measurement in the same initial state. As increasing the intensity of the coherent field and the strength of dipole-dipole interaction between atoms, the evolution of occupancy of atom C outside cavity can exhibit obviously the collapse-revival phenomenon and the characteristic of increasing of Rabi frequency and lengthening of revival period, etc.

Design and implementation of FPGA-USB-based control board for quantum experiments are discussed. Usage of quantum random number generator, control-logic in FPGA and communication with PC though USB protocol are proposed. Flexible control-signal outputs and inputs are implemented. It has frame auto-sync function when frame error appears.

Based on the Lyapunov stability and matrix theory, two schemes are used to estimate the unknown jump parameters of one certain chaotic circuit and complete synchronization is realized. Theoretical analysis is given and checked by the numerical simulation. Within the first scheme, some unknown jump parameters(parameters jump suddenly) are identified completely by stabilizing the chaotic system to stable state and the critical value for negative feedback coefficient can be found by calculating the conditional Lyapunov exponents of the controlled system. Within the second scheme, parameter observers and controllers with controllable gain coefficient are approached theoretically by using the Lyapunov stability theory. Five unknown parameters are estimated exactly within short transient period when the two chaotic circuits reach complete synchronization. The two schemes are compared and discussed in brief.

Based on analysis of the characteristics of ultrashort optical soliton, influences of third-order dispersion (TOD) and Raman scattering were taken into account. The relationships between and were obtained by using the numerical simulation method, analysis method and fitting method. It improves the self-frequency shifting formula which considered Raman scattering only. The volume of the pulse delay caused by the self-frequency shifting was also studied. The result indicates that the amount frequency shifting caused by TOD is , the amount pulse delay is , the pulse delay caused by TOD is . This result is very important for the high-speed optical switch.

In order to obtain the effect of temperature on the interactions of screening-photovoltaic bright spatial solitons in two-photon photovoltaic photorefractive media, taking the two mutually coherent optical beam as the input wave, the beam propagation equation is solved numerically under different temperatures. The result shows that the interaction of two in-phase solitons still has fusions along with temperature varying in the room temperature range. With the raising of the temperature of media to 350 K, two in-phase solitons fuse a solitary wave. With the varying of the temperature, the repulsions of two out-of-phase solitons are increasing. The repulsions and the energy transferring increase with the varying of the temperature for the -phase-difference solitons. Two solitons crash in the interactions process when the varying is great enough.

An ordinary prism coupling surface waves (SW) sensor and grating-assisted SW sensors are studied using rigorous coupled-wave-analysis method. The material parameters and structural parameters of the one-dimensional photonic crystal and grating are designed, which works under 1550 nm. The depth of grating is 20 nm, the pitch is 524.6 nm, and the duty cycle is 0.5. Simulation shows that grating leads to the emergence of dual-resonance dip, and the surface mode is splitted. The use of double resonance dip characteristics can improve sensitivity of the perspective of an ordinary prism structure SW sensor more than 3 times.

The structure of multi-point fiber Bragg grating (FBG) was adopted to monitor the situation of seepage in dam. It used the wavelength demodulation method which applied InGaAs photoelectric detector array to measure the light intensity. According to the laboratory data, possibility of the multi-point fiber grating sensor system and reliability of the measured data are analyzed. Results showed that the wavelength-temperature response sensitivity of the fiber grating sensor can reach 0.0091 nm/℃ of the temperature field in the dam. Engineering application showed that using the electric heat pulse method to heat the soil around sensors formed the temperature difference with the water, the actual measurement result showed that the method which uses fiber grating to detect temperature difference can apply to monitor seepage. It can realize the positioning of concentrated seepage points in the dam and automatic monitoring. Compared with conventional instruments, the fiber grating sensing monitoring system has obvious advantages in resistance to thunderbolts and disturbances.

Nd:YAG nanoscaled powders were prepared by the co-precipitation method with Nd2O3, Y2O3 and Al(NO3)3?9H2O as the starting materials and CO(NH2)2 as the precipitator. The structure and morphology of the powders were investigated by XRD, TG-DTA, FESEM and laser particle analyzer. XRD patterns show that YAG phase and intermediate phase YAM were detected in the sample from the precursor calcined at 900 ℃ for 3 hours, the precursor completely transformed to YAG phase when it was calcined at 1000 ℃ for 3 hours, and the intensity of YAG X-ray diffraction peaks increased with the increase of calcination temperature. Lattice parameters of Nd:YAG phase calcined at 900 ℃~1200 ℃ changed from 1.2012 nm to 1.1994 nm, and the particle size ranged from 31~96 nm. The similar variation was given by a measure of laser particle analyzer. The TG-DTA results indicate that the mass loss value was about 43% when the precursor was heated up to 1200 ℃. Suspension was washed with distilled water and alcohol, respectively. The comparison results show that alcohol is more effective for the well-dispersion of the nano-sized Nd:YAG powders. The results provid references for preparing good powders of YAG transparent ceramics.

Ag nanoparticles are prepared by microwave synthesizing method and absorbed on the glass slide by self-assembling technology. Thus, the localized surface plasmon resonant (LSPR) sensor is developed. UV-vis absorption spectrum shows that its LSPR peak is located at 428nm in pure water. The LSPR peak takes red shift when the refractive index of surrounding solution increases, and the sensitivity can arrive at (173±6) nm/RIU. After annealing at 350 ℃, the shape of Ag nanoparticles on the glass slide is changed. The LSPR peak shifts about 65 nm towards longer wavelength, and the sensitivity decreases with 20%. Theoretical analysis indicates that shape and substrate take important effect on the response of wavelength and the sensitivity for the refractive index sensor of Ag nanoparticles.