In order to restore turbulence-degraded images rapidly and exactly, an accelerated iterative blind deconvolution (IBD) Richardson-Lucy (R-L) algorithm based on Huber regularization is proposed. The Huber function can select L1 and L2 norms adaptively based on the processing result of image filter. In the smooth area, the Huber function becomes the usual L2 least-squares penalty function with rapid convergence characteristics which can remove false edge, and in the edge area, the L1 penalty function which can maintain the detail information and edge. Then the second-order vector extrapolation acceleration technique is used to accelerate convergence rate. The experimental results show that the proposed algorithm has greater convergence rate and better subjective and objective restoration quality.
Aimed at the problem of not taking into account both precision and efficiency, a novel ridges extraction algorithm based on “image” segmentation is proposed. For an asymptotic signal, its continuous wavelet coefficients with large absolute values usually distribute in some dispersed regions in the time-scale plane. Taking the absolute wavelet coefficients matrix as an “image”, the wavelet ridge can be detected by segmenting the “image” and locating the maximum value from each region. Experimental results show that the proposed algorithm not only outperforms general algorithms with respect to precision and efficiency, but also works well in signal denoising and signal separation.
The transient response of silicon p-i-n photodiodes irradiated by femtosecond laser with a range of pulse energy levels was investigated experimentally. The spatiotemporal response exhibits three clearly chronological phases. The role of high-injection induced by femtosecond laser effects on the evolving spatiotemporal response was discussed. The results indicate that the space-charge screening effects lead to three clearly separable collection phases with ambipolar diffusion primarily determining the length of the induced transient response signal. Increased femtosecond laser pulse energy levels would further elongate the transient length which would severely degrade the performance of photodetector especially in the high speed signal detection.
Using the splitting-operator spectral method, the evolution of interaction of the pulse laser with hydrogen atom system was stimulated. The result indicates that when the input laser pulse is sine waves, the Rabi oscillation is also sine waves. When the input laser pulse is amplitude-modulated pulse, the Rabi oscillation will be of square waves, but there exists serious population-leak. Besides, when the hydrogen system is under a confined potential energy, the laser intension can be decreased to decrease the population-leak and achieve complete population transfer.
A scheme of two-way quantum teleportation controlled by a third party was proposed. Two sides of communication (Alice and Bob) and the controller Charlie shared a six-qubit cluster state in advance. Firstly, Alice and Bob performed Bell-state measurements(BSMs) on parts of their qubit pairs, respectively. If Charlie agreed them to communication, he should measure his qubits and announce their states. According to Charlie’s measured results, the two sides of communication performed some appropriately unitary transformations on their qubits respectively. Then they were able to reconstruct each other’s unknown state on their own qubits. The security of two-way communication was improved because of the control of the third party.
Aiming at the enlarging scale of quantum logic circuits and the degradation of reliability, a new online error detection method based on single quantum gate is proposed. A new signal generation gate and an error detection gate are designed by the method and the parity-preserving characteristics are used to detect the error of the circuits. In the meantime, the method can detect the signal generation gate, ensuring the correctness of the gate. In addition, a new self-repairing method for quantum logic circuits based on hardware redundancy is given. The results show that the new method can detect all the error with less quantum gates and garbage outputs, and the first-realized self repairing method increases the fault-tolerance capability and reliability of the quantum circuits.
A scheme of teleportation of a N-particle entangled GHZ state through a two-paticle entangled quantum channel was proposed. Firstly, the maximally entangled states were taken as quantum channels, then the case of nonmaximally entangled channels was considered. It was found that by implementing H transformation and von Neumann measurement, introducing an ancilly qubit, when the channels are nonmaxially entangled states, constructing an unitary transformation properly, teleportation of three-paticle entangled GHZ state cound be implemented with certain probability. Finally, the N-particle entangled GHZ state was discussed. Compared with other schemes, this scheme saves the quantum entanglement channel resources.
In Markovian environment, the nature of entanglement dynamics and entanglement sudden death of coupling qubits in the dissipative environment are investigated in detail using concurrence function. The results show that the dynamic evolution of entanglement is closely related with temperature of the system, the initial entanglement and the initial quantum state. Under normal circumstances, entanglement sudden death always occurs due to environmental effect. A specific area is found through numerical simulation where the decay of entanglement is very slow. Under the zero-temperature approximation, the specific conditions of entanglement sudden death and the equation for calculating the time of entanglement sudden death are both given.
To build the transmission damage model of quantum entanglement signaling in free space, the relationship between transmission distance and signaling damage degree was proposed. A relay scheme of quantum entanglement signaling and its repairing strategy were put forward. The simulation results show that transmission damage degree is closely related to transmission distance and positioning loss under the three conditions of the telescope’s aperture of the sending and receiving ends and transmission factor and the carrier photons wavelength are constant. And the positioning loss has a little effect on the transmission damage degree. Therefore, the transmission distance is the main factor of the signaling damage. Quantum signaling long distance transmission in free space need to add on repeaters.
Using two-level approximation with the Bloch-Redfield equation, the flux quantum qubit decoherence was investigated in superconducting qubit circuit affected by the mutual inductance’s influence under super-Ohm thermal reservoir environment. The results show that, firstly under the super-Ohm thermal reservoir environment, the improvement of the environmental indicator coefficient can help to extend the decoherence time of the superconducting flux qubits, thus improving the magnetic flux qubits decoherence. Secondly, building super-Ohm thermal reservoir environment can improve the solid-state qubit decoherence. Finally, the effects of the mutual inductance coupling between the inductive elements on quantum circuit system’s decoherence are more complicate, good regulation of the mutual inductance between the inductive coupling elements can help to improve the decoherence time.
With Kramers theory and Wentzel-Kramers-Brillouin (WKB) approximation theory, the thermal escape and macroscopic quantum tunneling behaviors of the metastable state in a three-junction flux qubit are investigated. At temperature ranging from 0.01 K to 4.2 K, the escape rate is calculated, the switching distribution which varies with magnetic field and temperature is worked out and the case of superconducting interferometer is also compared quantitatively. The results show that self-noise of three-junction flux qubit is bigger than that of superconducting interferometer.
Based on the SU(2) group structure of Jaynes-Cummings model, its time evolution operator were obtained by using the algebraic method. As an application of the solution, the exact result of state |Ψ(t)? of the system evoluting with time at any given time t in the condition that the initial state of system is |e,n? was given. Then, the probability Pe(t) of finding the atom in excited state |e? at time t was obtained in the condition that the initial state of the system is |g,α?. The superiority of the solution was discussed lastly.
A two-dimensional photonic crystal consisting of two square arrays of square dielectric columns with different sizes in air is proposed and investigated theoretically. For the proposed structure, Maxwell’s equations are Fourier transformed rigorously, and a plane-wave expansion method with fast convergence is then formulated. With this method, the band structure of the photonic crystal is numerically analyzed carefully. It is shown that compared with the related structure with a single square lattice, the absolute band gap of the proposed structure is remarkably increased after optimizing the geometric parameters, owing to the decrease of the structural symmetries.
In terms of split-step Fourier transform method, the numerical solution of nonlinear Schr?dinger equation is obtained. The interaction of first-order self-Fourier optical soliton in optical fibers is studied numerically. It is proved that there is not any theoretical error in the inner part of algorithm. The results of numerical simulation show that: 1) The interaction between a couple of first-order self-Fourier solitons are different from first-order standard soliton. It is similar to the interaction between a couple of second-order solitons or a couple of second-order quasi-solitons. The solitons repel each other even more strongly after an initial attraction stage. 2) It is not enough to recognize and classify the characteristics of interaction between two solitons according by the order of soliton. The different pulse width have the different influences to the interaction of solitons or in the same order. 3) A little third-order dispersion may restrict the interaction between the neighboring first-order self-Fourier solitons.
Using the variational method, influence of the amplifier spontaneous emission (ASE) noise upon the optical pulse in dispersion management system is discussed, thus, the pulse phase variance, central time variance and center frequency variation with distance are obtained. And influence of the ASE noise is discussed in the densely dispersion managed soliton system and the larger negative average dispersion. The numerical simulation results show that the densely dispersion managed soliton system and the larger negative average dispersion can reduce the pulse impact of ASE noise.
In order to investigate soliton phenomenon in optical fiber induced by the dispersion and nonlinearity with structure of double pitfalls, the (1+1)-dimensional nonlinear Schr?dinger (NLS) equation with variable coefficients was discussed by employing a numerical split-step Fourier code. There exist a series of interesting properties of optical fiber solitons in two types of optical nonlinear systems with the structure of double pitfalls, such as the periodic oscillations of one soliton pulse induced by the nonlinear structure of double pitfalls based on the variable parameter background, the walk-off effect of two solitons induced by the nonlinear structure of double pitfalls based on the constant parameter background, the special interaction and the fusion reactions of three solitons in two types of optical nonlinear systems with the structure of double pitfalls.
In order to investigate influence of the substrate temperature and distance on diamond-like carbon (DLC) films in the pulsed laser deposition (PLD), firstly the temperature was kept at 200C to deposit DLC film when the graphite target located at 25.0 mm and 30.0 mm from substrate respectively, secondly the temperature was kept at 400C to deposit DLC film when the graphite target located at 25.0 mm and 30.0 mm from substrate respectively. The microstructure of DLC films was detected by the visible Raman spectroscopy. The topography of DLC films was detected by the atomic force microscopy (AFM). The experimental result demonstrates that ratio of sp3/sp2 and the density of DLC film decrease and size and number of graphitic crystallites increase when the temperature or distance increases. The smaller is the distance, the bigger is the influence of temperature on the microstructure of DLC film. The lower is the temperature, the bigger is the influence of the distance on the microstructure. The distance and temperature should influence topography of DLC film obviously.
A pattern recognition named phase-only matched filtering is presented to realize high precision alignment in projecting lithography. The method achieves the alignment with the characteristic direction of templates and silicon substrate using the coherent peak rotating sensitive feature in the filter. Meanwhile the relative translation distance of templates and silicon substrate is obtained in recognition algorithms. Such an alignment system is assembled in our mature projection lithography machine, and the experimental data obtained prove the higher accuracy and efficiency compared with conventional algorithms.
In order to deal with quantum mobile communication system handover, the handover algorithm of quantum mobile communication based on entanglement degree computing is proposed. According to the alteration of user’s location, it defines entanglement degree on quantum mobile terminal and the antenna of quantum base station firstly. Then various impact factors of entanglement degree are analyzed. Then analysis and calculations are carried out for the mobile users to handover between the various sectors finally. The results show that the proposed handover algorithm of quantum mobile communication based on entanglement degree computing has a good operability and can be realized. The algorithm plays an important technical support role in building the future quantum mobile communication systems and standard setting.