The second-order temporal interference of two independent single-mode continuous-wave lasers is discussed by em- ploying two-photon interference in Feynman＇s path integral theory. It is concluded that whether the sec...The second-order temporal interference of two independent single-mode continuous-wave lasers is discussed by em- ploying two-photon interference in Feynman＇s path integral theory. It is concluded that whether the second-order temporal interference pattern can or cannot be retrieved via two-photon coincidence counting rate is dependent on the resolution time of the detection system and the frequency difference between these two lasers. Two identical and tunable single-mode continuous-wave diode lasers are employed to verify the predictions. These studies are helpful to understand the physics of two-photon interference with photons of different spectra.展开更多
Owing to the unique feature that the signal and reference waves of self-interference digital holography(SIDH)contain the same spatial information from the same point of object,compared with conventional digital hologr...Owing to the unique feature that the signal and reference waves of self-interference digital holography(SIDH)contain the same spatial information from the same point of object,compared with conventional digital holography,the SIDH has the special spatial coherence properties.We present a statistical optics approach to analyzing the formation of cross-correlation image in SIDH.Our study reveals that the spatial coherence of illumination light can greatly influence the imaging characteristics of SIDH,and the impact extent of the spatial coherence depends substantially on the recording distance of hologram.The theoretical conclusions are supported well by numerical simulation and optical experiments.展开更多
Wireless Body Area Network(WBAN) is an emerging technology to provide real-time health monitoring and ubiquitous healthcare services. In many applications, multiple wireless body area networks have to coexist in a sma...Wireless Body Area Network(WBAN) is an emerging technology to provide real-time health monitoring and ubiquitous healthcare services. In many applications, multiple wireless body area networks have to coexist in a small area, resulting in serious inter-network interference. This not only reduces network reliability that is especially important in emergency medical applications, but also consumes more power of WBANs. In this paper, an inter-network interference mitigation approach based on a power control algorithm is proposed. Power control is modeled as a non-cooperative game, in which both inter-network interference and energy efficiency of WBANs are considered. The existence and uniqueness of Nash Equilibrium in the game are proved, and an optimal scheme based on best response is proposed to find its Nash Equilibrium. By coordinating the transmission power levels among networks under interference environment, the total system throughput can be increased with minimum power consumed. The effectiveness of the proposed method has been illustrated by simulation results, where the performance of the proposed approach is evaluated in terms of overall utility and power efficiency and convergence speed.展开更多
The second-order interference of two independent photons with different spectra in a Shih-Alley/Hong-Ou-Mandel interferometer is studied in Feynman's path integral theory. There is a second-order interference patt...The second-order interference of two independent photons with different spectra in a Shih-Alley/Hong-Ou-Mandel interferometer is studied in Feynman's path integral theory. There is a second-order interference pattern for photons with different spectra if the photons are indistinguishable for the employed detection system. The conditions to observe the second-order temporal beating with photons of different spectra are analyzed. The influence of the response time of the detection system on the observed second-order interference pattern is also discussed. It is a direct result of that measurement in quantum mechanics is dependent on the employed measuring apparatus. The results are helpful to understand the physics of two-photon interference in different schemes.展开更多
The real time domain interferometry for the photodetachment dynamics driven by the oscillating electric field has been studied for the first time. Both the geometry of the detached electron trajectories and the electr...The real time domain interferometry for the photodetachment dynamics driven by the oscillating electric field has been studied for the first time. Both the geometry of the detached electron trajectories and the electron probability density are shown to be different from those in the photodetachment dynamics in a static electric field. The influence of the oscillating electric field on the detached electron leads to a surprisingly intricate shape of the electron waves, and multiple interfering trajectories generate complex interference patterns in the electron probability density. Using the semiclassical open-orbit theory, we calculate the interference patterns in the time-dependent electron probability density for different electric field strengths, different frequencies and phases in the oscillating electric field. This method is universal, and can be extended to study the photoionization dynamics of the atoms in the time-dependent electric field. Our study can guide the future experimental researches in the photodetachment or photoionization microscopy of negative ions and atoms in the oscillating electric field.展开更多
The second-order temporal interference of classical and nonclassical light at an asymmetrical beam splitter is discussed based on two-photon interference in Feynman＇s path integral theory. The visibility of the secon...The second-order temporal interference of classical and nonclassical light at an asymmetrical beam splitter is discussed based on two-photon interference in Feynman＇s path integral theory. The visibility of the second-order interference pattern is determined by the properties of the superposed light beams, the ratio between the intensities of these two light beams, and the reflectivity of the asymmetrical beam splitter. Some requirements about the asymmetrical beam splitter have to be satisfied in order to ensure that the visibility of the second-order interference pattern of nonclassical light beams exceeds the classical limit. The visibility of the second-order interference pattern of photons emitted by two independent single-photon sources is independent of the ratio between the intensities. These conclusions are important for the researches and applications in quantum optics and quantum information when an asymmetrical beam splitter is employed.展开更多
To solve the problems with the existing methods for detecting hollowing defects,such as inconvenient operation,low efficiency and intense subjectivity,and to improve the efficiency of the acoustic-optic fusion method ...To solve the problems with the existing methods for detecting hollowing defects,such as inconvenient operation,low efficiency and intense subjectivity,and to improve the efficiency of the acoustic-optic fusion method for detecting hollowing defects,in this paper the vibration characteristics of hollowing defects are measured and analyzed using a laser self-mixing interferometer.The ceramic tile above the hollowing defect is equivalent to a thin circular plate with peripheral fixed support.According to Kirchhoff's classical circular plate theory and the circular plate displacement function based on the improved Fourier series,a theoretical model of a circular plate is established.By solving the characteristic equation,the theoretical modal parameters of hollowing defects are obtained.Subsequently,an experimental system based on a laser self-mixing interferometer is built,and modal experiments are carried out using the hammering method.The experimental modal parameters are obtained with a professional modal analysis software.Through comparative analysis between the theoretical and experimental modal parameters,the error of the natural frequency results is found to be tiny and the mode shapes are consistent.These results provide theoretical guidance for a practical non-destructive acoustic-optic fusion method for detecting hollowing defects.展开更多
Wireless sensor networks are suffering from serious frequency interference.In this paper,we propose a channel assignment algorithm based on graph theory in wireless sensor networks.We first model the conflict infectio...Wireless sensor networks are suffering from serious frequency interference.In this paper,we propose a channel assignment algorithm based on graph theory in wireless sensor networks.We first model the conflict infection graph for channel assignment with the goal of global optimization minimizing the total interferences in wireless sensor networks.The channel assignment problem is equivalent to the generalized graph-coloring problem which is a NP-complete problem.We further present a meta-heuristic Wireless Sensor Network Parallel Tabu Search(WSN-PTS) algorithm,which can optimize global networks with small numbers of iterations.The results from a simulation experiment reveal that the novel algorithm can effectively solve the channel assignment problem.展开更多
In this paper, we propose a semi-classical theory to successfully explain the polarization flipping in a single frequency laser. An experimental setup is built to verify this theory. The observed experimental phenomen...In this paper, we propose a semi-classical theory to successfully explain the polarization flipping in a single frequency laser. An experimental setup is built to verify this theory. The observed experimental phenomena are consistent with the theoretical analysis. We perform phase retardation measurements of birefringent components using this experimental system. The results show that the measurement repeatability is 0.12° and the measurement accuracy is 0.22°.展开更多
We report the design of a novel multiband metamaterial bandpass filter （BPF） in the terahertz （THz）-wave region. The designed BPF is composed of a metal-dielectric-metal sandwiched structure with three nested ring...We report the design of a novel multiband metamaterial bandpass filter （BPF） in the terahertz （THz）-wave region. The designed BPF is composed of a metal-dielectric-metal sandwiched structure with three nested rings on the top surface and a cross structure on the bottom surface. Full-wave simulation results show that the designed BPF has three transmission peaks at frequencies of 0.42, 1.27, and 1.86 THz with transmission rates of-0.87,-1.85, and-1.83 dB, respectively. Multi-reflection interference theory is introduced to explain the transmission mechanism of the designed triple-band BPF. The theoretical transmission spectrum is in good agreement with the full-wave simulated results. The designed BPF can maintain a stable performance as the incident angle varies from 0 to 30 for both transverse electric and transverse magnetic polarizations of the incident wave. The designed BPF can be potentially used in THz devices due to its multiband transmissions, polarization insensitivity, and stable wide-angle response in the THz region.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11404255)the Doctor Foundation of Education Ministry of China(Grant No.20130201120013)
文摘The second-order temporal interference of two independent single-mode continuous-wave lasers is discussed by em- ploying two-photon interference in Feynman＇s path integral theory. It is concluded that whether the second-order temporal interference pattern can or cannot be retrieved via two-photon coincidence counting rate is dependent on the resolution time of the detection system and the frequency difference between these two lasers. Two identical and tunable single-mode continuous-wave diode lasers are employed to verify the predictions. These studies are helpful to understand the physics of two-photon interference with photons of different spectra.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.91750202,91750114,and 11922406)the National Key Research and Development Program of China(Grant Nos.2018YFA0306200 and 2017YFA0303700)the Science and Technology Project of Jiangxi Provincial Education Department,China(Grant No.GJJ190915).
文摘Owing to the unique feature that the signal and reference waves of self-interference digital holography(SIDH)contain the same spatial information from the same point of object,compared with conventional digital holography,the SIDH has the special spatial coherence properties.We present a statistical optics approach to analyzing the formation of cross-correlation image in SIDH.Our study reveals that the spatial coherence of illumination light can greatly influence the imaging characteristics of SIDH,and the impact extent of the spatial coherence depends substantially on the recording distance of hologram.The theoretical conclusions are supported well by numerical simulation and optical experiments.
基金supported by the National Natural Science Foundation of China (No.61074165 and No.61273064)Jilin Provincial Science & Technology Department Key Scientific and Technological Project (No.20140204034GX)Jilin Province Development and Reform Commission Project (No.2015Y043)
文摘Wireless Body Area Network(WBAN) is an emerging technology to provide real-time health monitoring and ubiquitous healthcare services. In many applications, multiple wireless body area networks have to coexist in a small area, resulting in serious inter-network interference. This not only reduces network reliability that is especially important in emergency medical applications, but also consumes more power of WBANs. In this paper, an inter-network interference mitigation approach based on a power control algorithm is proposed. Power control is modeled as a non-cooperative game, in which both inter-network interference and energy efficiency of WBANs are considered. The existence and uniqueness of Nash Equilibrium in the game are proved, and an optimal scheme based on best response is proposed to find its Nash Equilibrium. By coordinating the transmission power levels among networks under interference environment, the total system throughput can be increased with minimum power consumed. The effectiveness of the proposed method has been illustrated by simulation results, where the performance of the proposed approach is evaluated in terms of overall utility and power efficiency and convergence speed.
基金Project supported by the Key Research and Development Project of Shaanxi Province,China(Grant No.2019ZDLGY09-08)the Open Fund of MOE Key Laboratory of Weak-Light Nonlinear Photonics,China(Grant No.OS19-2)the Fundamental Research Funds for the Central Universities,China
文摘The second-order interference of two independent photons with different spectra in a Shih-Alley/Hong-Ou-Mandel interferometer is studied in Feynman's path integral theory. There is a second-order interference pattern for photons with different spectra if the photons are indistinguishable for the employed detection system. The conditions to observe the second-order temporal beating with photons of different spectra are analyzed. The influence of the response time of the detection system on the observed second-order interference pattern is also discussed. It is a direct result of that measurement in quantum mechanics is dependent on the employed measuring apparatus. The results are helpful to understand the physics of two-photon interference in different schemes.
基金Project supported by the National Natural Science Foundation of China(Grant No.11374133)the Taishan Scholars Project of Shandong Province,China(Grant No.ts2015110055)
文摘The real time domain interferometry for the photodetachment dynamics driven by the oscillating electric field has been studied for the first time. Both the geometry of the detached electron trajectories and the electron probability density are shown to be different from those in the photodetachment dynamics in a static electric field. The influence of the oscillating electric field on the detached electron leads to a surprisingly intricate shape of the electron waves, and multiple interfering trajectories generate complex interference patterns in the electron probability density. Using the semiclassical open-orbit theory, we calculate the interference patterns in the time-dependent electron probability density for different electric field strengths, different frequencies and phases in the oscillating electric field. This method is universal, and can be extended to study the photoionization dynamics of the atoms in the time-dependent electric field. Our study can guide the future experimental researches in the photodetachment or photoionization microscopy of negative ions and atoms in the oscillating electric field.
基金supported by the National Natural Science Foundation of China(Grant No.11404255)the Doctor Foundation of Education Ministry of China(Grant No.20130201120013)+1 种基金the Programme of Introducing Talents of Discipline to Universities,China(Grant No.B14040)the Fundamental Research Funds for the Central Universities,China
文摘The second-order temporal interference of classical and nonclassical light at an asymmetrical beam splitter is discussed based on two-photon interference in Feynman＇s path integral theory. The visibility of the second-order interference pattern is determined by the properties of the superposed light beams, the ratio between the intensities of these two light beams, and the reflectivity of the asymmetrical beam splitter. Some requirements about the asymmetrical beam splitter have to be satisfied in order to ensure that the visibility of the second-order interference pattern of nonclassical light beams exceeds the classical limit. The visibility of the second-order interference pattern of photons emitted by two independent single-photon sources is independent of the ratio between the intensities. These conclusions are important for the researches and applications in quantum optics and quantum information when an asymmetrical beam splitter is employed.
基金Project supported by the National Key Research and Development Program of China(Grant No.2023YFF0722900)the Beijing Engineering Research Center of Aerial Intelligent Remote Sensing Equipments Fund(Grant No.AIRSE20233)the National Natural Science Foundation of China(Grant No.62175144)。
文摘To solve the problems with the existing methods for detecting hollowing defects,such as inconvenient operation,low efficiency and intense subjectivity,and to improve the efficiency of the acoustic-optic fusion method for detecting hollowing defects,in this paper the vibration characteristics of hollowing defects are measured and analyzed using a laser self-mixing interferometer.The ceramic tile above the hollowing defect is equivalent to a thin circular plate with peripheral fixed support.According to Kirchhoff's classical circular plate theory and the circular plate displacement function based on the improved Fourier series,a theoretical model of a circular plate is established.By solving the characteristic equation,the theoretical modal parameters of hollowing defects are obtained.Subsequently,an experimental system based on a laser self-mixing interferometer is built,and modal experiments are carried out using the hammering method.The experimental modal parameters are obtained with a professional modal analysis software.Through comparative analysis between the theoretical and experimental modal parameters,the error of the natural frequency results is found to be tiny and the mode shapes are consistent.These results provide theoretical guidance for a practical non-destructive acoustic-optic fusion method for detecting hollowing defects.
基金supported by National Key Basic Research Program of China(973 program) under Grant No. 2007CB307101National Natural Science Foundation of China under Grant No.60833002,No.60802016,No.60972010+1 种基金Next Generation Internet of China under Grant No.CNGI-0903-05the Fundamental Research Funds for the Central Universities under Grant No.2009YJS011
文摘Wireless sensor networks are suffering from serious frequency interference.In this paper,we propose a channel assignment algorithm based on graph theory in wireless sensor networks.We first model the conflict infection graph for channel assignment with the goal of global optimization minimizing the total interferences in wireless sensor networks.The channel assignment problem is equivalent to the generalized graph-coloring problem which is a NP-complete problem.We further present a meta-heuristic Wireless Sensor Network Parallel Tabu Search(WSN-PTS) algorithm,which can optimize global networks with small numbers of iterations.The results from a simulation experiment reveal that the novel algorithm can effectively solve the channel assignment problem.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61036016)the Scientific and Technological Achievements Transformation and Industrialization Project of the Beijing Municipal Education Commission, China
文摘In this paper, we propose a semi-classical theory to successfully explain the polarization flipping in a single frequency laser. An experimental setup is built to verify this theory. The observed experimental phenomena are consistent with the theoretical analysis. We perform phase retardation measurements of birefringent components using this experimental system. The results show that the measurement repeatability is 0.12° and the measurement accuracy is 0.22°.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11504418,11447033,and 61372048)the Fundamental Research Funds for the Central Universities,China(Grant No.2015XKMS075)
文摘We report the design of a novel multiband metamaterial bandpass filter （BPF） in the terahertz （THz）-wave region. The designed BPF is composed of a metal-dielectric-metal sandwiched structure with three nested rings on the top surface and a cross structure on the bottom surface. Full-wave simulation results show that the designed BPF has three transmission peaks at frequencies of 0.42, 1.27, and 1.86 THz with transmission rates of-0.87,-1.85, and-1.83 dB, respectively. Multi-reflection interference theory is introduced to explain the transmission mechanism of the designed triple-band BPF. The theoretical transmission spectrum is in good agreement with the full-wave simulated results. The designed BPF can maintain a stable performance as the incident angle varies from 0 to 30 for both transverse electric and transverse magnetic polarizations of the incident wave. The designed BPF can be potentially used in THz devices due to its multiband transmissions, polarization insensitivity, and stable wide-angle response in the THz region.
