Stochastic Resonance in a Single-Mode Laser Driven by Pump Noise and Quantum Noise with Cross-Correlated Real and Imaginary Parts

We present an analytic investigation of the signal-to-noise ratio (SNR) by studying a signal modulated model of a single-mode laser system driven by pump noise and quantum noise with correlated real and imaginary parts,and find there is a maximum in the curve of the dependence of SNR upon the cross-correlation coefficient λq between the real part and the imaginary part, i.e., stochastic resonance appears in the SNR vs. λq curve. Moreover, when the SNR is at the maximum, the cross-correlation coefficient λq = O, which is coincidentally at the minimum of the mean normalized intensity fluctuation. The influences on stochastic resonance by the intensities of the pump and the quantum noise, the amplitude of the modulation signal, and the net gain of the laser are also studied. Furthermore, in order to ensure that the results obtained in this paper is reliable, the valid range for the linear approximation method is discussed.     

Stochastic Resonance in a Single - Mode Laser Driven by Pump Noise and Quantum Noise with Cross-Correlated Real and Imaginary Parts

We present an analytic investigation of the signal-to-noise ratio (SNR) by studying a signal modulated model of a single-mode laser system driven by pump noise and quantum noise with correlated real and imaginary parts,and find there is a maximum in the curve of the dependence of SNR upon the cross-correlation coefficient λq between the real part and the imaginary part, i.e., stochastic resonance appears in the SNR vs. λq curve. Moreover, when the SNR is at the maximum, the cross-correlation coefficient λq = 0, which is coincidentally at the minimum of the mean normalized intensity fluctuation. The influences on stochastic resonance by the intensities of the pump and the quantum noise, the amplitude of the modulation signal, and the net gain of the laser are also studied. Furthermore, in order to ensure that the results obtained in this paper is reliable, the valid range for the linear approximation method is discussed.     

Noise Immunity of a Laser Receiver with an Iodine Active Quantum Filter

The effect of a wide-range background exposure on the sensitivity of a laser receiver with an iodine quantum filter ( =1.315 m) is theoretically investigated. The sensitivity of the laser receiver is shown to be only about 12% less than the quantum limit when detecting optical signals against the background of the solar disk. It is also shown that in the case where the radiance temperature of a blackbody considered as a source of background radiation is 1.6· 10⁴ K, a twofold decrease in the sensitivity of the laser receiver is expected. The sensitivity of the receiver discussed is compared with that of a receiver with a visible-range photomultiplier tube. In the case of detection of optical signals against the background of the solar disk, the sensitivity of a receiver with an FEU-115 photomultiplier tube and interference filter ( 5 nm) is approximately 400 photons when the signal-to-noise ratio of the receiver is equal to unity.     

外腔锁模多量子阱二极管激光器

报道一种用作光通讯光源的外腔锁模多量子阱结构半导体激光器，其脉冲宽度２～５ｐｓ，波长调谐范围为１．５２～１．５７μｍ，锁模频率０．５～１．０ＧＨｚ平均输出光功率为１ｍＷ。     

Quantum Information Splitting of an Arbitrary Three-Atom State in Cavity Quantum Electrodynamics

A cavity quantum electrodynamics scheme for implementing the deterministic quantum information splitting of an arbitrary three-atom state is proposed. In the scheme, a genuine five-atom entangled state and a Bell-state can be used as the quantum channel, which does not involve Bell-state measurement and only needs to perform the single-atom measurements. Our scheme is insensitive to both the cavity decay and the atom radiation, and considered here is secure against certain eavesdropping attacks.     

非线性激光场中量子噪声之间的耦合效应

用二维气体激光模型对量子噪声的实部和虚部存在耦合的激光场进行了理论分析，通过福克－普朗克方程导出了定态激光光场强度和位相的分布函数，算出了定态激光强度和位相的平均值，方差和偏斜度，与量子噪声的两个分量为独立随机变量的激光场相比，噪声间的耦合极大地改变了激光场强度和位相的涨落，并引起了激光场强度与位相之间的耦合。     

在非对称光腔中利用CRIB技术进行光量子态存储

本文提出了一个在光腔中利用可控逆非均匀展宽技术实现高效的量子存储方案.当光场在光腔中每次往返的吸收与透射到光腔中光场强度完全一样时(阻抗匹配条件),发现进入光腔中的光场可以完全被非均匀展宽原子系综吸收.通过计算得到无论是向前读取还是向后读取的方案,量子存储效率在光深度很小时都可以达到1.若没有光腔100％的存储效率仅仅只有在光深度无穷大时才能得到.在光深度很小时就能达到高效的量子存储在实验上非常容易实现.因此该方案为实验上实现高效的量子存储提供一个确实可行的方法.     

Nonreciprocal Phonon Laser in an Asymmetric Cavity with an Atomic Ensemble

Phonon lasers, as a novel kind of lasers for generating coherent sound oscillation, has attracted extensive attention. Here, we theoretically propose a nonreciprocal phonon laser in a hybrid optomechanical system, which is composed of an asymmetric Fabry–Pérot cavity, an ensemble of N identical two-level atoms, and a mechanical oscillator. The effective driving amplitude related to driving direction leads to an obvious difference in mechanical gain and threshold power, bringing about a nonrecipr...     

Quantum Memory with Natural Inhomogeneous Broadening in an Optical Cavity

We propose an efficient quantum memory scheme with natural inhomogeneous broadening in an asymmetric optical cavity. The scheme uses the strong rephasing pulses like traditional photon echo techniques rather than spectral holeburning, which enables us to have the potential implementation in a much broader range of material systems. In the condition of impedance matching to an optical cavity, we find that the input light pulse can be completely absorbed by an atomic ensemble. We also show that the quantum memory efficiency can be equal to unity even for a small optical depth of the atomic system.     

A Heuristic Analysis of Quantum Noise Quenching in the Two-Photon Correlated Emission Laser

We demonstrate how the two-photon correlated emission laser (CEL) can be understood from a simple physical picture in a quasirigorous fashion. We use semiclassical arguments to derive correct expressions for the phase and amplitude diffusion in a simple way. We then illustrate how noise suppression is achieved in the two-photon CEL.     

Generation of Coupled Modes in an Unmatched Three-Mirror Laser Cavity

An extraordinary phenomenon of generation of coupled types of oscillations with a transverse field distribution corresponding to the ТЕМ _pq eigenmodes with different pairs of indices p and q in the main laser cavity and in an external cavity has been experimentally detected. The excitation of coupled modes depends on the configuration and tuning of partial cavities. To solve the system of integral equations for a three-mirror cavity with mismatched spherical mirrors in the quasioptical approximation, it has been proposed to use modified boundary conditions including the coupling coefficients for eigenmodes in partial cavities.     

New Stimulated Brillouin Laser with an Induced Cavity

JETP Letters - A paradoxical decrease in the generation threshold of high Stokes and anti-Stokes components of stimulated Brillouin scattering in water has been detected for the first time to our...     

Stochastic Resonance Induced by an Asymmetric Two-state Noise

Stochastic resonance (SR) phenomenon of the system that is subject to the asymmetric two-state noise is investigated from the broad sense. It is shown that the amplitudes of the output signal exhibit the non-monotonic dependence on the input signal frequency ω, and the parameters describing the asymmetric two-state noise, such as the transition rate λ, the order parameter k describing the asymmetric degree of the two-state noise, and the noise strength D.     

Stochastic Resonance Induced by an Asymmetric Two-state Noise

Stochastic resonance （SR） phenomenon of the system that is subject to the asymmetric two-state noise is investigated from the broad sense. It is shown that the amplitudes of the output signal exhibit the non-monotonic dependence on the input signal frequency w, and the parameters describing the asymmetric two-state noise, such as the transition rate A, the order parameter k describing the asymmetric degree of the two-state noise, and the noise strength D.     

自发辐射对量子级联激光器发光噪声的影响

为得到量子级联激光器特有的光噪声特性,通过在速率方程中引入Langevin噪声源以及自发辐射因子的方法,在单模与线性增益的情况下讨论了自发辐射因子及与偏置电流等参数与光噪声的强度及带宽等特性之间的关系,计算结果表明,增大自发辐射因子能降低光噪声的强度,增宽光噪声的3-dB截止频率,进一步的研究也表明,自发辐射因子对光噪声的影响与激光器的偏置电流有密切关系,这种影响在偏置电流较小时比较明显,但当偏置电流很大时自发辐射因子对光噪声的影响将变得很弱。     

COIL非稳腔实验的数值模拟

在薄层增益近似与非均匀加宽饱和增益系数条件下,用C-7程序对COIL非稳腔实验进行了数值模拟,计算所得结果对分析实验结果有一定参考价值。     

COIL非稳腔实验的数值模拟

 在薄层增益近似与非均匀加宽饱和增益系数条件下,用C-7程序对COIL非稳腔实验进行了数值模拟,计算所得结果对分析实验结果有一定参考价值。