Hollow-core Bragg fibers (HC-BFs) based on one-dimensional photonic bandgap (PBG) effect have flexible and convenient bandgap control capability and excellent performance in broadband and low-loss transmission. As a distinctive category of hollow-core PBG fiber, HC-BFs show great potential application in optical transmission, dispersion management and control, fiber-type devices, sensing detection and so on. The development and recent research progress of HC-BFs are reviewed, with regard to the structural design of fiber waveguide and guided wave modal propagation characteristics, cladding materials composition and fiber fabrication technologies, and their applications in trace-gas detection and biochemical sensing based on gaseous or liquid analyte-filled HC-BFs.

Hadamard multiplexing technology can effectively improve the signal-to-ratio of ion mobility spectrum, but the false peaks and other distorting phenomenon appear in Hadamard spectral, which has serious influence on the detection performance of ion mobility spectrometry(IMS). The changes of false peaks in Hadamard transform IMS are observed by changing the multiplexing parameters, and relationship between the multiplexing parameters and false peaks are analyzed. Experimental results show that variations of multiplexing parameters can change false peak position or peak profile, but they can not eliminate fundamentally false peak phenomenon of Hadamard IMS. Results further prove that the inherent defects in Hadamard multiplexinged modulation may be one of the main causes appearing the false peaks in Hadamard transform IMS.

Laser active illumination imaging has the advantages of long range, high resolution, obtaining the target image in complex environment such as low illumination background. However, the image is disturbed by speckle noise. Gaussian filtering, mean filtering and adaptive filtering methods are applied to the simulation experiment respectively for speckle noise suppression. Experiments show that compared with Gauss filtering and mean filtering, the adaptive filtering can effectively suppress image noise and keep edge and detail information of the image. Speckle suppression experiment for the obtained single frame and multi-frame cumulative average laser active detection image is carried out by using the adaptive filtering method. Quantitative analysis is carried out with speckle contrast ratio. Results show that the cumulative mean of multi-frame short exposure images can effectively suppress the image speckle noise. Adaptive filtering can further reduce the image speckle noise.

Aiming at the problem of target tracking lost or failure when the traditional mean shift algorithm uses fixed kernels or symmetric kernel function to track targets, an adaptive bandwidth mean shift target tracking algorithm based on anisotropic kernel function is proposed to improve the accuracy and real-time of target tracking. The signed distance constraint function is introduced based on the signed distance kernel function, and anisotropic kernel function is constituted, which meets that the function value is zero in external area of target, and provides accurate tracking window for target tracking. According to the fact that the mean shift based on anisotropic kernel function must meet the weights sum of the sample points to center point vectors in the tracking window is zero when applying to target tracking, the mean shift window centers of anisotropic kernel function templates are calculated. Restrictions on the target template change before and after are carried out by using similarity threshold, and the adaptive updating of the anisotropic kernel function template and accurate real-time tracking of the target are realized. Experimental results show that the proposed algorithm has higher accuracy and better real-time performance.

High-order harmonic emission and attosecond pulse generation from H+2 molecule driven by the spatial inhomogeneous laser field are theoretically investigated. Calculation results show that by properly adjusting the internuclear distance of H+2 molecule and spatial inhomogeneous parameters, the cutoff energy of harmonic emission is remarkably enhanced, and the interference structure of harmonic spectrum is also reduced. By introducing unipolar control laser field, the harmonic cutoff energy is further extended, and a 530 eV bandwidth long platform area contributed by a single quantum path is formed. By superposition of harmonics, a series of attosecond X-ray pulses with the pulse width ranging from 32 as to 46 as can be obtained.

High brightness synchrotron radiation light source and free electron laser（FEL） have higher requirements on the performance of linear accelerator coupling structure. The traditional single-side couplers induce asymmetry of electromagnetic fields in cavity due to the asymmetry of cavity structure, which greatly affects the beam quality. A new type of single-side coupler loaded with dielectric cylindrical rods is proposed. Its structure is simple, and easy to be processed. The simulation results show that dipolar and quadrupolar electric field amplitude gradient for the new coupler are －0.0794% and －0.066%, respectively, but the ones are 5.02%, 2.99% for the traditional couplers. The asymmetry of field amplitude is effectively weakened. The temperature field distribution, thermal deformation and thermal stress of coupler are analyzed and calculated. Results show that the new coupler has little difference with the usual single-side coupler in thermal performance, and is expected to improve the performance of light source.

Under control of applied laser pulse, the dynamical behavior of double cavity coupled system with a two-level quantum bit is investigated. Based on the system interaction Hamiltonian, the analytical solutions of system quantum state excited probability are obtained. The system dynamic characteristics are discussed by numerical simulation in three specific cases. In the case of applied laser resonating with cavity, bit and cavity field mismatching, the maximum excitation probability of cavity mode is less than 0.07. The cavity mode is in a non-excited state, and the bit excitation probability appears instantaneous decay. Under the condition of strong coupling between bit and cavity mode, the excitation probability of cavity mode is approximately 0.5. The cavity mode is in the state of semi-excitation, and the bit excitation probability appears high frequency oscillation. Under the condition of large jumping between cavity fields, the maximum excitation probability of cavity mode is less than 0.07. The cavity mode is in the non-excited state, and the bit excitation probability appears high frequency oscillation.

Pseudo-thermal light is a regular source for correlated imaging. Compared to entangled two-photon source of quantum state, it can be easily obtained and used in correlation experiment. Pseudo-thermal light and entangled two-photon have certain similarities, especially in statistic characteristics of light field, which is closely related to the correlated calculation. When the quantum field is a coherent state or classically-random mixture of coherent states, statistic characteristics of the quantum field and classical field are all the same. The zero-mean Gaussian state can be used to describe fully the phase-insensitive coherence propagation of pseudo-thermal light. Based on this model, semi-classical detection theory of pseudo-thermal light is established. The correlation calculation formula of photocurrent in reference path and signal path are derived. The resolution and contrast of ghost imaging and view field of correlated imaging system are analyzed.

Entanglement characteristics in a system of a two-level atom interacting with a number-phase state (NPS) field are investigated by using the fully quantum theory. The entanglement degree expression of the system is calculated. Influences of the initial atomic state, parameters of field phase, largest-photon number, parameters of light field and transition photon number on the system entanglement degree are analyzed. Results show that when the initial atomic state is in superposition state, and the field phase parameter is small relatively, the system entanglement degree is large relatively. When the appropriate largest-photon numbers and transitional photon numbers are chosen, the smaller the field parameter is, the more obvious the entanglement phenomenon will be.

Aiming at the effective mapping problem of reversible circuits to quantum circuits, a big mutation adaptive genetic algorithm with tabu list is proposed for the synthesis of quantum reversible circuits. The quantum gate library is formed by choosing the quantum NOT gate, controlled-NOT gate (CNOT), controlled-V gate and controlled-V+ gate. The quantum circuit calculation model is established. The binary serial coding scheme is adopted, and the fitness function, evolutionary operators and optimization rules are designed. The synthesis of quantum reversible circuits that use big mutation adaptive genetic algorithm with tabu list is realized, and tested by the circuit library named Revlib. Results show that the comprehensive method can get multiple functional solutions at the same time, and the cost of the generated circuits is better than that of the circuits in Revlib. The correctness and effectiveness of the proposed algorithm for the synthesis of quantum reversible circuits are verified.

Constraints and limitations of quantum circuits must be considered in synthesis of quantum circuits. In certain quantum technologies only physically adjacent qubits are allowed to interact with each other. Linear nearest neighbor architecture must be used when implementing. It is common to bring the control and target qubits of any quantum gate to adjacent lines by adding SWAP gates, and the circuit function is ensured not be affected. A new method for constructing linear nearest neighbor quantum circuits is proposed based on analysis of quantum bit state in circuit. Results show that the proposed scheme can reduce the quantum cost by approximately 30% on average comparing with the existing schemes for all 40320 three-qubit quantum circuits.

By combining the numerical-parameterized optimized effective potential (NPOEP) model and pseudospectral method, the high-harmonics generation(HHG) process of alkaline metal atoms in intense laser field is investigated. The evolution matrix is modified based on the features of NPOEP model. The orthogonality of time-dependent wave function with closed-shell orbit in evolution process is ensured. The mid-infrared laser field with a wavelength of 3038 nm and intensity of about 1013 W/cm2 is chosen as the driving field, and the high-order-harmonic spectra of lithium, sodium and potassium atoms are calculated. Contributions of bound state transition harmonics of Rydberg state sodium atom on harmonic generation are investigated. Results show that the resonance of Rydberg and ground state can make the low-order harmonic intensity increase by one order of magnitude. It is verified that the method is reliable in describing the process of electron recapture during time evolution.

Accurate acquisition of cavity ring-down signal is the basis of quantitative detection of gas concentration by cavity ring-down spectroscopy. Aimed at the characteristics of cavity ring-down signal, a cavity ring-down signal acquisition and processing system based on FPGA is designed. FPGA is used as main controller of system. The system realizes high speed acquisition of the cavity ring-down signal, accumulation average of the corresponding point and transmission of the USB data under excitation of trigger signal. Tests show that the system has good accuracy and stability (accuracy in the range of 4 per thousand). When applied in cavity ring-down system, the consistency of data from the data processing system and foreign data acquisition card can reach 99.4%. Results show that the data acquisition and processing system can fully meet the acquisition requirements of cavity ring-down signal.

In the thermal radiation measurement technology, the nonlinear effect of infrared detector leads to some error in target infrared radiation measurement. Based on blackbody radiation law, the thermal radiation curve of blackbody at different temperatures and certain wavelength and bandwidth is calculated theoretically. The thermal radiation measured by infrared detector is obtained experimentally with the same parameters. The detection curve of detector is modified by the theoretical curve. The nonlinear effect of detector is corrected, and the measurement accuracy of thermal radiation temperature measurement is improved.

The expression of Gaussian envelope solitonin Schrdinger equation is given and proved. According to the Gaussian envelope soliton, Gaussian envelope soliton interaction situation existing in Schrdinger equation is further proposed. The symplectic algorithm for solving Schrdinger equation is proposed. The Schrdinger equation is transformed into the standard Hamiltonian canonical equation by separating the real and imaginary parts of wave function, and the symplectic algorithm is implemented by using Euler center difference separation for the canonical equation. The conserved quantity of symplectic algorithm is given, and its stability is proved. The numerical simulation is carried out on Gaussian envelope soliton motion and multi-soliton interaction in Schrdinger equation. Experimental results prove the correctness of the proposed method and validity of symplectic algorithm.

Based on the eigenvalue equation and finite-difference time-domain (FDTD) algorithm, the surface plasmon resonance sensing characteristics of rhombic gold nanoparticle arrays embedded in silica substrate are investigated, and relationship between the resonance mode and embedded depth is derived. The calculated results agree with the numerical simulation, which shows that the asymmetry of the upper and lower media of gold nanoparticle arrays can be equivalent to monolayer dielectric grating. The physical mechanism and influence factors of generating multiple resonance peaks in the transmission spectra are analyzed theoretically. Relationships between the transmission spectrum and embedded depth, axial ratio, array period are further discussed. The sensing performance of array structure is analyzed. It provides a theoretical basis for the fabrication of multi-band surface plasmon resonance(SPR) sensor substrate.

The properties of polaron in nanotubes are invesgated by combination of solving the energy eigen-equation, unitary transformation and variation method. Numerical calculation results indicate that the energy of ground state and first excited state of polaron increases with increasing nanotube inside radius or decreasing nanotube outside radius, which illustrates that the nanotubes have obvious quantum size effect. It decreases with increasing of the electron-phonon coupling strength. The interaction between the electron and phonon leads to the absolute value increasing of interaction energy and decreasing of the polaron energy. It increases with increasing wave vector along the nanotube orientation. Increasing wave vector of the direction leads to increasing of the electron kinetic energy, and the energy of polaron increases.

Based on linear combination operator and variational method, the qubits and its phonon effects of electron phonon interaction system, in which the coupling of electron and surface optical (SO) phonon is strong, the coupling of electron and bulk longitudinal optical phonon is weak, are discussed in polar crystal film. When the electron is in the superposition state of the ground state and first excited state, the probability density of electrons is periodically oscillating in space. Results show that the oscillation period decreases with the increasing of coupling strength, and increases with the increasing of polaron vibration frequency. Considering the interaction between electron and SO phonon, the polaron vibration frequency changes, which causes the change of probability density of the electron.