三次谐波系统混沌态光场统计中的高阶距

本文研究了三次谐波系统混沌态光场中光子数高阶矩的统计行为，结果表明，系统参数不仅对高阶矩取值有影响，而且对出现基波大于谐波同阶高阶矩的临界阶数取值也有影响，此外，在同一混沌态吭阶的值基本上随阶数单调增大。     

双模压缩真空场与N型四能级原子双光子跃迁相互作用系统中光场的量子特性

精确求解了双模压缩真空场与Ｎ型四能级原子双光子跃迁相互作用系统的波函数，并讨论了系统中光场的压缩效应及光子的统计性质．数值计算结果表明，光场的两个正交分量的均方涨落均呈现周期性的压缩，其压缩程度与系统的初始状态有关；光场光子的统计性质也依赖于系统的初始状态，光场两模之间的相关是一种非经典相关．     

三次谐波系统混沌态光场统计中的高阶矩

本文研究了三次谐波系统混沌态光场中光子数高阶矩的统计行为,结果表明,系统参数不仅对高阶矩取值有影响,而且对出现基波大于谐波同阶高阶矩的临界阶数取值也有影响．此外,在同一混沌态中高阶矩的值基本上随阶数单调增大。     

混沌激光光场的统计性质

我们研究了由Maxwell-Bloch方程所描述的单模激光混沌态的一些统计性质。 在相干光场与非相干光场迭加的模型下,混沌激光光场的几率分布函数是高斯型,光子起伏方差表现出混沌激光光场具有聚束过程。一阶相干函数     

光场在压缩态中的平均值及相位涨落

本文证明了光场在压缩态中的平均值具有经典电磁波的类比形式。并根据相位与光子数的测不准关系式计算了光场相位在压缩态中的涨落,找出此涨落与平均光子数及压缩因子的关系,证明了平均光子数越大时,光场越接近稳定的经典电磁波。     

脉冲式赝热光源的实验研究

高亮度的辐照热光源一定程度上限制了基于经典热光场的强度关联量子成像技术的实验研究和广泛应用.因为一般热光源相干时间极短,且每个相干元胞内光子数少(亮度低),而采用激光照射旋转毛玻璃形成的动态散斑作为赝热光场可以解决上述问题.当采用的是纳秒脉冲激光时,得到的赝热光场除了能极大程度地模拟真实热光场的热涨落,光场涨落服从真实热光场所具有的高斯统计分布以外,另一个最重要的特性是光场涨落的测量不受光电探测系统有限通频带的限制,即使是慢响应探测电路,也能准确地记录光场抖动,即该光场符合交叉谱纯条件.     

Kerr介质中双模奇偶纠缠相干光场与Ⅴ型三能级原子相互作用系统的光子统计性质

采用求解SchrSdinger方程和数值计算方法，研究了Kerr介质中双模奇偶纠缠相干光场与Ⅴ型三能级原子相互作用系统的光子统计性质，分析了双模奇偶纠缠相干光场的纠缠度、Kerr介质与光场的耦合强度、双模光的平均光子数、失谐量和原子基态概率幅对光子统计性质的影响。结果表明：双模奇偶纠缠相干光场的纠缠程度对光子统计性质的影响不十分明显；Kerr效应增强使演化曲线上下移动，曲线的振荡频率变大、振荡幅度变小；保持场模1的光子数不变而改变场模2的光子数，会使演化曲线向上或向下显著移动、曲线的振荡幅度发生变化；失谐量的改变对光子统计特性也有一定影响；原子初态中基态概率幅的变化使演化曲线上下显著移动。     

双光子Jaynes—Cummings模型的亚泊松光子统计特性研究

本文利用量子电动力学理论和缀饰原子方法，对双光子Ｊａｙｎｅｓ０Ｃｕｍｍｉｎｇｓ模型中单模激光场的稳态亚泊松光子统计性质进行了系统研究。结果表明：激光上能级相对泵浦参量Ｘａ具有一个确定的阈值Ｘａｔ；当Ｘａ〉Ｘａｔ时，光场呈现亚泊松光子统计；而当Ｘａ》Ｘａｔ时，光场将呈现出深度且完全恒定的亚泊松光子统计。     

多光子过程中光场的位相特性

本文应用Pegg-Barnett位相理论研究了光场在与原子的多光子相互作用过程中位相的几率分布,期待值和涨落等。     

双光子Jaynes－Cummings模型的亚泊松光子统计特性研究

本文利用量子电动力学理论和缀饰原于方法，对双光子Ｊａｍｅｓ－Ｃｕｍｍｉｎｇｓ模型中单模激光场的稳态亚泊松光子统计性质进行了系统研究。结果表明：激光上能级相对泵浦参量Ｘａ具有一个确定的阈值Ｘａｔ；当Ｘａ＞Ｘａｔ时，光场呈现亚泊松光子统计；而当Ｘａ＞＞Ｘａｔ时，光场将呈现出深度且完全恒定的亚泊松光子统计。     

Sub-Poissonian and super-Poissonian photon statistics in atwin-core doped optical fiber

In this paper, we develop a quantum statistical theory of light propagation in a twin-core doped optical fiber. The optical nonlinearity induced by the atomic dopants in the fiber dramatically modifies the quantum fluctuations in the paraxial photon modes. We find that with appropriate arrangement of the device, the input light field with the usual Poissonian photon statistics can be transformed into sub- or super-Poissonian photon statistics. For the sub-Poissonian photon statistics, the quantum noise in the photon numbers in the paraxial modes is reduced below the level of the noise in the usual laser field     

利用单光子探测器测量多光子响应时间

通过研究单光子探测器对微弱激光脉冲的暂态响 应特性,利用不同光子数的响应时间实现光 子数的分辨测量。理论上分析了光子数响应时间与微弱光脉冲探测时间的对应关系。实验上 通过测量不同光强下单光子探测器的暂态响应,测量到1550nm波段单光子、 双光子和三光子的响应时间分别为10.73±0.17、8.75±0.32和5.98±0.77ns。实现精确区分微弱光场中的光子数。分析了单光子探测器光子数统计涨落引起的 微弱激光脉冲的探测时间变化对光子数响应时间测量的影响。     

Laser experiments with single atoms as a test of basic physics

Two experiments with single atoms are reviewed. In the first experiment, the interaction of a single Rydberg atom with a single mode of an electromagnetic field was investigated. The quantum collapse and revivals of the atomic inversion predicted by the Jaynes-Cummings model were demonstrated for the first time. In the second experiment, a single atomic ion stored in a radio-frequency trap was probed by resonance fluorescence. In the fluorescent light, antibunching and sub-Poissonian photon statistics were detected. Furthermore, `crystallization' and `evaporation' of few ions in a trap were observed as the stored ions were cooled by the laser light and heated by the radio-frequency field of the trap     

Photon statistics and quantum jumps: the picture of the dressedatom radiative cascade

The statistics of spontaneous photon emission times in single atom resonance fluorescence are investigated through the radiative cascade of the dressed atom. The delay function which gives the distribution of the delays between two successive emissions is calculated for a coherent as well as an incoherent laser excitation. For a two-level atom, various signals that reflect the fluorescence intensity (average value, photon counting, fluctuation spectrum, etc.) are reviewed by this method. For a three-level atom, this approach is applied to the analysis of the recently observed phenomenon of intermittent fluorescence and quantum jumps     

Single-atom cavity-enhanced absorption. I. Photon statistics in thebad-cavity limit

The photon statistics of the transmitted light from a driven cavity containing a single resonant two-level atom are studied in the bad-cavity limit. For weak driving fields, the second-order intensity correlation function shows novel nonclassical behavior due to the interference of the driving field and forward reradiation from the atom. This behavior is related to squeezing in the cavity transmission. A physical interpretation is given in terms of the reduced quantum state of the coupled atom-field system following photodetection     

Spatially antibunched semiconductor laser beam forsub-shot-noise-limited apertured transmission

It is shown that, using a semiconductor laser, one can generate spatially antibunched light. This light displays a smaller variance when measured over finite spatial regions than light from a classical source. In analogy with the common (temporal) amplitude-squeezed light, which possess photon statistics that are more regularly spaced in time than a Poissonian, this spatially amplitude-squeezed light produces a beam having photon statistics that are more highly correlated across its transverse extent than the typical (having Poissonian detection statistics) laser beam. One may have a spatially amplitude-squeezed source which does not display temporal squeezing, and one may have a temporally amplitude-squeezed source which does not display spatial amplitude squeezing. The possibility of having both forms of amplitude squeezing simultaneously is considered and such a device, using semiconductor laser technology, is proposed. Analysis reveals that there is indeed a quantum correlation between different segments of the beam. This spatially antibunched light suffers less signal-to-noise degradation when spatially partitioned in the object or subsequent image planes, making it potentially superior in spatial light modulation, free-space transmission, or imaging applications     

激光斜程湍流大气传输平均偏振起伏

运用光子密度分布函数和采用大气折射率起伏Von Karmam湍流谱、研究了相干激光通过斜程大气传输时的平均量子偏振起伏。通过唯象方法导出大气折射起伏对光场相位调制关系,从而建立了斜程大气光子密度分布函数模型。基于斜程湍流大气光子密度分布函数导出了平均＂量子偏振度＂的解析关系。结果指出：湍流大气导致光束偏振度起伏满足零均值高斯分布,大气湍流不影响光子偏振度统计平均值。     

多光子反J-C模型下纠缠相干光场量子特性研究

利用多光子反Jaynes-Cummings(J-C)模型,研究了双模纠缠相干光场中一束光与受强经典场驱动的二能级原子相互作用时光场的量子特性,讨论了跃迁光子数、时间、光场初态等参量对未参加相互作用光场的反聚束效应和压缩效应的影响.结果表明:改变跃迁光子数、时间及选取参加相互作用光场的初态等参量,能使未参加相互作用的光场...     

Quantum theory of third-harmonic generation in a gaseous system--Part I

We present a theoretical treatment for third-harmonic generation in gaseous systems by describing the atomic system as well as the radiation field quantum mechanically. The atomic system is represented by two energy levels. The effects of detuning in the two-photon interactions and the atomic motion on the third-harmonic generation are taken into account. The photon statistics of the third-harmonic field are obtained. The average photon number, second-order coherence, and output variance of the third-harmonic field are discussed. The above results show a nonlinear dependence on the detuning in the two-photon interactions and the Doppler parameter.