A laser reference interferometer to eliminate the distortion of recovery spectrum caused by piezoelectric ceramic’s non-linear modulation in fiber Fourier transform spectrometer (FFTS) was desingned. It can offer equal sampling intervals for sampling tested source, and the basis calibration for the tested spectrum. The interference signal of 632.8 nm He-Ne laser is acquired by the fiber Michelson interfermeter (FMI). Fourier transform algorithm is used to calculate the spectrum. The difference between the spectrum acquired by the experiment and traditional grating spectrometer which can present helpful reference to develop FFTS further was also analyzed.

A new method for locating fingerprint singular points based on discrete Fourier transform (DFT) of orientation field and corner detector is proposed. Orientation field is processed in frequency domain via DFT so that noise is better suppressed. Fingerprint singular points are located by corner detection and clustering based on object labeling. Novel properties, which reveals the relationship between singular points and corners, are derived based on pole/zero model of orientation field. Experimental results show improved accuracy of singular points location and a reduced processing time.

A fusion method for polarimetric image based on Contourlet transform is proposed. Owing to the geometric information, Contourlet transform is a flexible multi-scale, multi-direction and shift-invariant image decomposition. It is easily adjustable for detecting fine details in any orientation along curvatures, which results in more potential for effective analysis of images compared with wavelet transform. The three polarimtric images in 555 nm band are decomposed using Contourlet transform. Low-pass coefficients and the directional high-frequency coefficients, which were calculated with the energy of the corresponding neighbor region, are used to select the better coefficients by weighted sum of algorithm for fusion. Experimental results show that the algorithm can get better visual effect and achieve the virtue of polarimetric image effectively and preserve image details, and the significant information of original image like textures and contour details is well maintained compared with the wavelet transform algorithm.

By using the classical Lie group method, explicit solutions to the (2+1) dimensional Gardner equation are obtained, which generalize some corresponding results obtained by Tang and Chen, and symmetries, symmetry reductions and group invariant solutions to the equation are presented.

To describe the interaction of laser and medium accurately, the semi-classical vector theory for elliptical mode is presented. From the self-consistent field equations, the limitations of the circular vector theory are analyzed. Based on the elliptical mode eigenvector, the elliptical vector theory formula is derived and discussed. The discussion shows that, the elliptical vector theory is in accordance with actual physical mode and has specific physical meaning, which evolves into circular vector theory when ellipticity is zero and accords with the experiment results well part-quantitatively. It is helpful to improve the part-classical theory and ring laser.

A kind of scattering is discussed and the corresponding distribution function is deduced. The geometry of the gain area is analyzed, the spatial distribution of output laser is obtained by simulating the movement of stochastic photon in random medium through the Monte Carlo method. The results show that the laser intensity is the strongest in the normal direction. It weakens gradually with the angle increasing. The light intensity is symmetrical on the normal. The spatial distribution of output laser is connected with the mean free path of photons in random medium. According to these, the mean free path of the photons can be obtained by measuring the spatial distribution of output laser. The majority of output laser photons (generally above 95%) scatter out within the distance of three mean free path from the interface.

A scheme is proposed for realization of three-qubit Toffoli gate for two intracavity modes with a five-level atom through the atom-cavity resonant interaction in a cavity quantum electrodynamics system. In the presented protocol, the two quantized cavity-field modes act as the two controlling qubits and the two stable ground states of the atom form the target qubit. The numerical simulation shows that the cavity-field decay is the dominant noise source in the dissipative process when both the atomic spontaneous emission and the decay of the cavity modes are taken into account during the gate operation. The influence of the deviation of the coupling strength on fidelity of the three-qubit Toffoli gate and the experimental feasibility of our proposal are also discussed.

A novel scheme for realizing a two-qubit quantum SWAP gate in ion-trap systems is proposed. Two three-level ions are considered which are confined in a linear trap interacting with two different frequency laser pulse in the case of resonance. According to the experimental methods and results of Haffner and Riebe, one Zeeman level of the S1/2 ground state of 40Ca+ ion can act as one ground state, while two Zeeman levels of the metastable D5/2 state as the excited states. With choosing appropriate parameters such as v=1.2 MHz, Ω=0.1v and η=0.1, the total time required to complete the procedure is T≈1.3×10ˉ3s, much shorter than the lifetime Ti≈1.16s of the metastable D5/2 state, and in this scheme decoherence is negligible. Thus this scheme may be realized with presently available ion-trap techniques.

At present, the most important problem of quantum key distribution is how to realize the key transmission for long distance and high key generation rate. Dual detectors are used in quantum key distribution and simulations are performed for BBM92 quantum key distribution system with ideal and parametric down conversion sources. Simulation results demonstrate improvements of keys generation rate in BBM92 protocol using dual detectors, as well as lower error bit rate. Secure communication distance can reach 300km when ideal sources are introduced and 250km with parametric down conversion sources.

A physical scheme for teleporting unknown atomic entangled states via three-atom non-maximally entangled states is proposed in cavity QED. The distinct advantages of the scheme are that the teleportation and distillation procedure can be realized simultaneously, and the scheme is insensitive to the cavity decay and thermal field with the assistance of a strong classical driving field. It is also unnecessary to concentrate non-maximally entanglement state quantum channel in advance. In addition, the joint Bell-state measurement can be distinguished via detecting the atomic state.

Highly entangled states called cluster states are an universal resource for measurement based quantum computing (QC). Based on the Josephson charge qubits, a scheme for generating cluster states is proposed. The scheme is simple and easily manipulated, because any two charge qubits based on Josephson junction can be selectively and effectively coupled by a symmetric dc superconducting quantum interference device (SQUID). Initially state can be generated via changing the gate voltages, and couple charge qubits by choosing the suitable parameters. All the devices in the scheme are within the current technology.

The quantum entanglement of three-level atoms, which include a V-type three-level atom, a V-type three-level atom and a Λ-type three-level atom, interacting with two-mode SU(1,1) coherent states in a high Q cavity with Kerr medium is studied. By numerical method, the influences of field parameters and Kerr effect on the quantum entanglement are discussed in detail. The result shows the laws of the three type atoms are coincident with the effect of Kerr in a high Q cavity with Kerr medium, before Kerr parameter reaches a certain value the quantum entanglement increases rapidly. However, the quantum entanglement is reduced when the parameter is over the certain value.

Monodisperse silica microspheres were assembled into a three-dimensional colloidal crystal template with long-range order by the solvent vaporization convection self-assembly method. Using GeH4 as the precursor gas, the plasma enhanced chemical vapor deposition method was then used to fill the voids of the silica colloidal crystal template with high refractive index germanium, then silica colloidal crystals template was removed by acid etching. Thus germanium inverse opal photonic crystal was obtained. The modality, components, structure and optic capability of the resulting samples were characterized by scanning electron microscope and X-ray diffraction and Fourier transform microscopic IR spectroscopy. The results show that germanium is homogeneously distributed inside the voids of the silica template. The crystalline state of germanium is polycrystalline state. Germanium inverse opal exhibits a three-dimensional ordered porous structure. The spectrum of the samples has optic reflective peaks and shows the photonic band gap effects. The complete three-dimensional bandgap lies in mid-infrared (about 3.4 μm) and optical capability is inosculated with the calculation.

Based on Fabry-Perot cavity’s theories and efficiency refractive index, the optical bistability of a nonlinear microcavity is studied, and the corresponding mathematical formula are deduced. The theoretical curves are well fitted with those of numerical simulation in other papers. The investigation shows that appropriate frequency-shifting should be preset on the incident light in order to produce bistability for a nonlinear system. If the system is composed of focusing nonlinear medium, the frequency must be red-shifted, otherwise it must be blue-shifted. The magnitude of critical shifting is 0.866 times of the width of microcavity resonance mode.

The nonlinear generalized Schr?dinger equation is applied to describe the propagation of femtosecond laser pulses and supercontinuum generation in a microstructured optical fiber, and solved by using the split-step Fourier method. And the role of self-steepening, intra-pulse stimulated Raman scattering(SRS) and third-order dispersion are discussed adequately. The numerical results show that solition self-frequency shift is generated in a microstructured optical fiber. It is also found that intrapulse stimulated Raman scattering and self-phase modulation result in spectral broadening based on the fission of higher order solitions, and two lagging solitions occur in the time domain. The third-order dispersion and self-steepening influence on the shape of spectrum little, having the opposite effects with SRS. Self-steepening has relatively bigger influence on the ultra-short laser pulse than the third-order dispersion.

The dispersion and nonlinear property of dispersion flattened photonic crystal fibers(PCF) with different structural parameters were numerically analyzed using beam propagation method. Dispersion coefficient D, effective mode area Aeff and nonlinear coefficient were calculated. The relationship between D, γand pitch Λ, hole diameter d was analyzed. The results indicate that dispersion and nonlinear property of dispersion flattened photonic crystal fiber can be controlled by the structural parameters Λ,d. In the range from 1300 nm to 1600 nm, PCF’s dispersion achives about -1.5 ps?kmˉ1?nmˉ1, and non-linear cofficient is above 19 Wˉ1?kmˉ1.

The pulse compression is affected by group-velocity dispersion parameter (GVD) and nonlinear parameter of the anomalous-dispersion compensative fiber in self-similar pulse compression technique. This effect was studied with numerical calculation based on nonlinear Schr?dinger (NLS) equation. The results show that compensative fiber’s GVD parameters affect compression factor and peak power of compressed pulse periodically. Pulse energy concentrates, disperses, and then concentrates in every period. As the magnitude of GVD parameter increases, period interval becomes longer and more energy diverts. Every time when energy concentrates, the pulse width approaches the compression limit. Optimal fiber length is a decreasing function of the magnitude of GVD parameter, but it has nothing to do with nonlinear parameter. On the other hand, the increase of nonlinear parameter reduces compression factor, which is bad for pulse compression. By optimizing the parameters of the compensative fiber, pulse width can attain its limit and high quality pulse is obtained.

Based on the nonlinear Schr?dinger equation, pulse propagation in fiber and the linearly chirped parabolic pulse generation by the dispersion decreasing fiber with a normal dispersion (ND-DDF) with a hyperbolic profile, a novel scheme for the generation of the self-similar parabolic pulse by use of a comb-like profiled fiber (CDPF) with normal group-velocity dispersion is proposed. The corresponding numerical model is also presented. In this model, evolution of the self-similar parabolic pulse in the CDPF close to dispersion profile of the DDF is analyzed numerically. The results show that when the hyperbolic-secant-like pulses at 1550 nm have different initial energy and pulse width, the pulse in the CDPF can evolve into a linearly chirped pulse with an exact parabolic intensity profile.

Influence of higher-order space-charge field on the self-deflection of a Gaussian beam is numerically investigated. The results indicate that, for a given photovoltaic-photorefractive crystal and a Gaussian beam which matches with its parameters, the effects of the higher-order space-charge field on self-deflection of Gaussian beam depend on the polarity and strength of the two field, extra electric field and photovoltaic field, and the incident optical intensity. When the extra electric field and photovoltaic field and incident optical intensity have different combination, the self-deflection can be controlled. At an especially combination, the change of deflection direction of Gaussian beam, and even stable transmit of Gaussian beam without deflection can be realized.

At the wavelength of 1064 nm, the absolute optical power responsivities of two Si trap detectors were measured against the cryogenic radiometer. The calibration method and experiment equipment were discussed, as well as analysis of the measurement data. A new quasi in-situ measurement scheme of Brewster windows transmittance was proposed and transmittance higher than 0.999 was obtained. Results show that the combined uncertainties of the responsivity are1.457×10ˉ4 and 1.458×10ˉ4, and the measurement repeatabilities of the two trap detectors were within 0.014% and 0.008%, respectively. The uncertainties and possible error sources during the process of measurement were analyzed and evaluated. The temperature stability of optical power responsivity of 0＃ trap detector was studied at the wavelength of 1064 nm.

During the neurosurgery brain damage surgery, real-time monitoring of the target’s regional physiological parameters is very important. There isn’t a credible method on real-time evaluation rule at present. Some elementary research was carried out in this aspect. SD rats were chosen as experiment object. The target of treatment local of rat brain was damaged with radio-frequency, and minimally invasive near-infrared technology was used to measure hemoglobin oxygen saturation in situ on real-time. The changes in the process of radio-frequency damage were studied. The different changes of hemoglobin oxygen saturation were studied in reversible damage and irreversible damage. At the same time, some basic law was found on the analysis of a large number of experiment parameters. The results have some efficacy in certain reference value in future damage of stereotactic radio-frequency real-time assessment.

Influences of the Coulomb field on the vibrational frequency and the mean number of optical phonons of weak-coupling impurity bound magnetopolaron in a parabolic quantum dot are studied using the linear-combination operator and the unitary transformation method. Expressions for the vibration frequency and the mean number of optical phonons of weak-coupling impurity bound magnetopolaron in a parabolic quantum dot as a function of the effective confinement length of quantum dot, the Coulomb bound potential and the cyclotron resonance frequency of magnetic field are derived. Numerical calculations are performed and the results show that the vibration frequency and the mean number or optical phonons of the weak-coupling impurity bound magnetopolaron in a parabolic quantum dot increase rapidly with decreasing of the effective confinement length of quantum dot, and increase with increasing of the cyclotron resonance frequency of magnetic field and the Coulomb bound potential. These can be attributed to the interesting quantum size effects.