Tunable photonic crystals(PC)draw rapidly growing interests in recent years. Practical applications in photonic devices provide a strong motivation to further development of dynamic tenability. The current progresses on tunable photonic crystal are reviewed from the aspects of the approaches,mechanisms,and materials. The tenability of photonic band gap on the condition of the change of the crystals structure parameters is described in details by utilizing the external force,electric field,magnetic field,and so on. The researches of changing the average refractive index of materials to control the band gap are also introduced,among which liquid crystal materials and electro-optic materials are mainly described. The advantages of different tunable methods are compared. Finally,the perspectives of the future research are briefly predicted .

The use of surface plasmon resonance(SPR)sensors is increasingly popular in fundamental biological research,drug discovery,public security and environmental monitoring areas,due to their advantages of label-free,high sensitivity,real-time and rapid detection. The development of surface plasmon resonance sensors will focus on the greater sensitivity,miniaturization,integration,low cost and reliability in the future. The prism coupling multi-layer composite configuration SPR sensors are introduced and emphasis is on the advance of fiber-coupled SPR sensors. Prospects of a high-throughput,multi-component identification surface plasmon resonance imaging technologies,as well as metal micro-nano structure(particles)localized surface plasmon resonance sensors are discussed.

The cause of open quantum systems,decoherence phenomena,its types,and its effects were analyzed and represented. Different kinds of methods and control strategies of suppressed decoherence were detailed summarized. The advantages and disadvantages of control strategies of suppressed decoherence in open quantum systems were exploited. In the end,the development direction of suppressed decoherence research was perspectived.

The Cs(7DJ)+H2→CsH[X1∑+(v″=0)]+H photochemical reaction was studied in a cell experiment by laser pump-absorption technique. Using two-photon exitation of the Cs72D atomic level in a Cs-H2vapor mixture,the resulting fluorescence includes a direct component arising from the optically excited state and a sensitized component due to the collisionally populated fine-structure state. The CsH molecules are formed in three-body reactive collisions between exited Cs72D atoms and ground state H2 molecules. Nearinfrared absorption band CsH X1∑+(v″= 0 →v′= 21)near 780 nm was measured. The cross sections for the 7D3/2→7D5/2 and 7D5/2→7D3/2 fine-structure mixing are(1.3±0.3)×10－14 and(9.8±2.0)× 10－15cm2,respectively. The cross sections for collisional transfer from 7DJ to states other than 7D for J being 3/2 and 5/2 are(4.0±1.0)×10－15 and(3.6±0.9)×10－15cm2,respectively. The reaction cross sections [i.e.,Cs(7DJ)+H2→CsH+H]for J being 3/2 and 5/2 are(1.4±0.5)×10－16 and(1.1±1.4)×10－16cm2,respectively. The relative reactivity with H2 for two studied atoms is in an order of Cs(7D3/2)>Cs(7D5/2).

Using 355 nm laser as excitation source,m-methylphenol multiphoton ionization and dissociation(MPID)was studied,m-methylphenol time-of-flight mass spectra of multiphoton ionization were obtained,There is no parent ion detected. The main possible dissociation and ionization channels were analysed. Using ab initio calculation to optimize the geometric structures of C7H8OH+ and C7H8OH at B3LYP/6-311++G(d,p)level,the stable structures are obtained. By exploring the potential energy surface of C7H8OH+,that the formation of C7H8OH+ is a reaction process without potential barrier is concluded.

The laser diode array(LDA)end-pumped intra-cavity second harmonic generation 525 nm green laser was demonstrated by using 1 mm thick Yb∶YAG crystal. The doping concentration is 10 at.%. The temperature of Yb∶YAG crystal was controlled by thermo-electric cooler(TEC). The nonlinear optical crystal,LBO,at a type-I phase-matching direction of(θ,φ)=(90°,12.2°)was employed. With linear-type cavity,a CW output power of 244 mw at 525 nm green laser has been obtained when the incident power was 11.3 W. The optical conversion efficiency was 1.98%.

The fiber end with polished inclined-surface is important to reduce the ASE and restrain the selfoscillations for the high power fiber amplifier. Physical models of fiber end with different signal input,output and coupling of pump light are set up. Theoretical analysis,numerical simulation of coupling efficiency and return loss of the fiber end with variable angles of the inclined surface are performed. The results show that the coupling efficiency and return loss of the signal light are affected obviously by the fiber inclined angle,which can improve the performance of the fiber amplifier if the angle is choosen properly.

The classic method to solve interaction between two-level atom and classic electric field is used to figure the several rates equation directly. The density matrix' method is used to establish the Hamiltonian operator of interaction between single two-level atom and classic electric field,and the differential equation is figured out,which is satisfied the density matrix of two-level atom system. The result shows that the density matrix non-opposite angle element never be zero at any time,and the quantum coherence characteristics of two-level atom system can keep well in this interaction model.

A scheme to realize the two-player quantum prisoner's dilemma with hot trapped ions is proposed. Based on the interaction between two ions and bichromatic radiation,the vibrational mode is only virtually excited so that the system is insensitive to the thermal field. In addition,since the basic logic gates of the quantum game can be constructed straightforward,the scheme is quite simple.

The quantum computation needs to maintain the quantum state coherent and the entanglement,but these two characteristics are very easy to be destructed by the decoherent process,therefore,how to overcome the effect of decoherence is the key to implement quantum computation. The Hamiltonian of the superconducting circuit was derived from circuit graph theory,and multilevel dissipative dynamics was studied by the Bloch-Redfield function. Finally,under two-level approximation,the influence of mutual inductance on the decoherence of the magnetic flux qubit was discovered. And how to change the mutual inductance to reduce the decoherence time of the magnetic flux quantum bit was discussed.

The quantum key distribution is discribed using fast polarization coding with polarization modulator and one laser. At the same time,the way of matrix analysis is used to study the process of the system. The results indicate that it is feasible to code and decode four non-orthogonal polarization states with phase-polarization modulator. The experiment of secret communication is successfully carried out based on 30 km fiber. The error rate is less than 6%.

The interaction between radiation and two-level atom was investigated by semi-classical theory and quantum theory respectively. The fidelity of the two-level atom's quantum state was written out. The influences of the radiation intensity in the case of semi-classical theory and the photon number of the radiation in the case of quantum theory on the fidelity were discussed for different atomic initial states. It is found that the fidelity of quantum state is independent of radiation intensity when the atom is initially in a superposition state and the atom interacts resonantly with the radiation field in semi-classical theory.The atom's quantum fidelity evolves periodically with time,and its frequency is modulated by radiation intensity. Furthermore,it can effectively change quantum information fidelity when the appropriate detuning.is selected.

The influences of radius-error and position-error of dielectric-rod on the properties of beam splitter,which is based on positive-negative refraction in photonic crystal,were investigated by numerical simulation with the frequency-difference time-domain method,respectively. It is found that the energy flow transmissivities of positive and negative refractive beams both remained more than 20% when the ratio of the radius-error amplitude and radius is less than 0.055 or the ratio of the position-error amplitude and lattice constant is less than 0.06.

The transmission spectra of 1-D photonic crystal of periodic positive-negative index structure at angular incidence was studied by transfer matrix method. The results show that the photonic band gap structure changes along with the change of incidence angle,especially for the dispersive 1-D photonic crystal composed of positve and negative refractive index materials,a new type of photonic band gap corresponding to zero of negative refractive index arises,of which the center is invariant upon the change of incidence angle,but the width broadens when the incidence angle increase;likewise,for a Bragg gap,the center and width of band gap change,which make the condition of achieving complete phase matching for the second harmonic effect.

Temperature effect on the self-deflection of Guassian beam in photofractive crystal is investigated by taking into account the temperature dependence of both diffusion effect and dark irradiation. Taking the Gaussian beam as the solitary beam,numerically solving the beam propagation equation in which the diffusion term has been taken into account,it is found that the center of the Guassian beam moves along a parabolic trajectory and,moreover the bending distance of the Guassian beam center increases first,reaches its maximum value at a specific. temperature,and after that decreases as temperature contionuously rises when the crystal temperature changes in a regime,whereas it will unstable or break down if the temperature change is large enough. The self-deflection of Gaussian beam in photovoltaic photorefractive crystal can be reshaped by appropriately adjusting the crystal temperature.

All-solid photonic crystal fiber has the unique property which can used to shift the zero-dispersion wavelength down to visible light,while maintain a large mode area which is one order of magnitude larger than that may be achieved in index guiding fiber. It can be a very valuable nonlinear material in dispersion compensation and high power soliton propagation,especially for the all-fiber devices. Numerical calculation is carried out for the simulation of nonlinear evolution in all-solid photonic crystal fiber with a modified general nonlinear Schr?dinger equation. The bandgap has strong effects on the suppression of soliton selffrequency shift during the nonlinear process. The effects of peak power of femtosecond laser,the bandwidth and central wavelength of the bandgap on the nonlinear process are also analyzed.

Using the parabolic potential as confinement potential in quantum dot and a five point difference method to discrete the Schr?dinger equations,a numerical self-consistent solution of 2D square GaAs quantum dot is carried out based on density-functional theory(DFT). The chemical potential and electron density are computed in the limit of zero temperature,and a comparison between chemical potential and the electron density under different confinement potentials is made.

Chaos theory is applied to electronic defiance. The approaches of chaos attacking and interfering optical fiber communication systems are proposed. Two methods of chaos masking attacking(CMAT)and chaos phase attacking(CPAT)are presented. In CMAT,the larger chaotic signal can mask straightway message signals and the small chaotic signal can interfere message signals to add bit-error-rate by state superposition principle. In CPAT,the chaotic signal can overprint the phase of the message signals by the cross-phase modulation so that chaos can interfere message signals. At last,optical fiber communication system at wavelength 1.31 for bit rates of 2.5 Gbit/s,5 Gbit/s and 25 Gbit/s are effectively attacked by CMAT and CPAT in simulations.

Based on modified nonlinear Schr?dinger equation,the differential equations for evolution of parameters of bright-soliton-like pulses in optical fibers were derived by using variational method,and the differential equations were numerically solved by Runge-Kutta algorithm. The result indicates that the third-order dispersion compresses or broadens the width,the initial chirp broadens the width,the thirdorder dispersion and initial chirp deduce shift of frequency and phase and bigger chirp. So small coefficient of the third-order dispersion and initial chirp is helpful to stable propagation of soliton-like pulses in fiber,and changing the symbol of the third-order dispersion is also helpful to propagation of bright-soliton-like pulses.