A Simulation of Near Field Optics by Three Dimensional Volume Integral Equation of Classical Electromagnetic Theory

A numerical simulation code for three dimensional problems of near-field optics has been developed using the volume integral equation with the moment method. The object is assumed to be continuous and macroscopic dielectric and can be treated by macroscopic Maxwell#x0027;s equations. The code can treat the large-scale moment method matrix that is obtained by the discretization of the volume integral equation. The resultant matrix equation is solved by an iteration method called the generalized minimum residual method with reasonable computational cost for simple problems of near field optics. Simulation of a simplified model of a scanning near-field optical microscope has been performed and basic polarization characteristics of the system have been investigated in detail. The code is also applied to the collection-mode of a photon scanning tunneling microscope, where the incident wave is the evanescent wave, and basic relation between near-field and far field i.e., output image, is recognized.     

A solution of radiative transfer in isotropic plane-parallel atmosphere by integrating Milne equation

In this paper we solve the inversion problem of the radiative transfer process in the isotropic plane-parallel atmosphere by iterative integrations of the Milne integral equation. As a result, we obtain the scattering function in the form of a cubic polynomial in optical thickness. The author has already solved the same problem by iterative integrations of Chandrasekhar's integral equation. In the Milne integral equation, both the cosines of the viewing angles and the optical thickness are integral variables, while in Chandrasekhar's integral equation the cosines of the viewing angles are variables but the optical thickness is not. We derive several series of exponential-like functions as intermediate derivations. Their convergences are evaluated by the author's previous work in the solution of Chandrasekhar's integral equation. The truncated scattering function up to the third order in optical thickness thus obtained is identical to that obtained from Chandrasekhar's integral equation, though their apparent forms are different. Chandrasekhar pointed out that the solution of Chandrasekhar's integral equation does not have a uniqueness of solution. The Milne equation, in contrast, has been proven to have a unique solution. We discuss the uniqueness of the solution by these two methods.     

光纤中单光子传输方程的求解及分析

量子信息在光纤中传输时,会受到光纤损耗、色散、非线性效应等多因素的影响,将产生传输态的演化与能量转移.本文以单模光纤传输方程以及电磁场量子化理论为基础,对单模光纤中基模模场进行量子化处理,推导并建立了考虑损耗、色散、非线性效应后的单光子传输方程.基于微扰法对单光子非线性传输方程进行了求解,给出了稳定解存在的必要条件及其所满足的色散方程.深入讨论了广域光功率随微扰频率的变化关系,并且分析了光纤色散、非线性效应对解的影响.为量子光纤传输系统性能的深入研究奠定了理论基础.     

Photon number and optical tomograms for Gaussian states

A review of probability representation of quantum states in given for optical and photon number tomography approaches. Explicit connection of photon number tomogram with measurable by homodyne detector optical tomogram is obtained. New integral relations connecting Hermite polynomials of two variables with Laguerre polynomials are found. Examples of generic Gaussian photon states (squeezed and correlated states) are studied in detail.     

基于激光等离子体的光子加速

利用一维动量方程、连续性方程和泊松方程,导出了由于短脉冲激光入射到稀薄等离子体中 而引起的电子密度扰动,它与入射激光密切相关.而密度扰动的传播形成电子等离子体波(尾 波场).利用光学度规的方法,研究了与驱动激光脉冲入射相距一定空间距离入射的尾随激光 脉冲由于尾波场的作用引起的光子频率的增大.结果表明,在一定条件下,入射到尾波场中 的光子可以从尾波场中获得能量,在光子总数不变时,光子频率会增大,光子获得加速. 关键词： 电子密度扰动 光学度规 光子加速     

太赫兹辐射场下的石墨烯光生载流子和光子发射

通过半经典的玻尔兹曼平衡方程理论研究了太赫兹辐射场下的石墨烯光生载流子和光子发射.研究得到了太赫兹辐射场下石墨烯的光生载流子浓度和光子发生率的解析公式.研究发现,掺杂电子浓度越小,或者温度越低,光生载流子浓度越大;掺杂电子浓度越大,或者温度越低,石墨烯的光子发射率越大.通过改变门电压或温度,可以有效地调控石墨烯光生载流子浓度和光子发射概率.理论研究结果和解析表达式对发展以石墨烯为基础的新型太赫兹光电器件具有重要的参考价值.     

Effect of optical aperture on the derivation of volume emission coefficient from side-on intensity measurements of cycling cylindrically symmetrical sources

An integral equation, analogous to the Abel integral equation for the derivation of volume emission coefficient from side-on observations, is developed which takes account of finite optical aperture. This integral equation is partially inverted and the solution is used to examine the effect of finite optical aperture for two simple distributions of volume emission coefficient.It appears that the error arising from the effect of finite optical aperture is negligible in most practical cases.One important and interesting result that emerges from this treatment is that the volume emission coefficient derived on the axis (r=0) is independent of optical aperture and is therefore correct whatever the aperture.     

Criterion for formation of the first bound state of an optical polaron

The ground state of an optical polaron has been analyzed for an arbitrary force of the electron-phonon coupling. The eigenvalue differential equation is transformed into the Fredholm integral equation. With the trace method applied to the kernel of integral equation, it is found that the first bound state of the optical polaron appears only provided that the dimensionless coupling constant obeys the inequality α_c≥2.8.     

全光波长变换器消光比特性的理论研究

半导体光放大器（SOA）是具有优良非线性效应的光子器件，在光开关、波长变换、光逻辑运算中有重要的应用。从SOA载流子的速率方程和耦合波方程出发，建立了基于SOA的交叉增益调制波长变换理论模型，并利用分段模型分析方法，对SOA的交叉增益调制波长变换的消光比特性进行了详细的研究。研究结果表明，适当增大信号光功率、减小探测光功率并选择合适的波长差和SOA长度，可以有效地提高传输信号的消光比。     

初始电子密度对光学薄膜激光损伤机制的影响

光学元件的激光损伤问题是激光器件向高功率密度方向发展中必须认识和克服的问题.基于Forkker-Planck方程,研究了激光与材料相互作用时的雪崩电离机制、多光子电离机制以及联合两种机制的情况.雪崩电离的产生需要一定密度的初始自由电子存在,该自由电子可以是材料中原本就存在的,也可能是光电离产生的.着重分析了材料中的初始自由电子对材料电离机制的影响.结果表明,雪崩过程在激光作用一段时间后会达到一个稳定的电离阶段（以自由电子平均能量不随时间变化为特征,且此时雪崩电离为材料电离的主导机制）,该时间与光电离速率、材料中初始自由电子密度有关.材料中的初始自由电子可以在一定程度上掩盖光电离的作用效果.
关键词:初始电子;激光损伤;光电离;雪崩电离     

Fundamental Studies of Photon Migration in Biological Tissues and Their Application to Optical Tomography

This paper reviews the studies of photon migration in biological tissues and its application to optical tomography which were conducted in the Mechanical Engineering Laboratory of Japan’s Ministry of International Trade and Industry. The research subjects range from theoretical and experimental studies of photon migration in random media to the development of image reconstruction algorithms and experiments for optical tomography. The most fundamental theoretical study of the photon diffusion equation has proved that the photon diffusion coefficient is independent of the absorption coefficient while the conventional one is dependent on the absorption coefficient. Experimental studies included the time-resolved spectroscopy and the fabrication of realistic human head phantoms which have five tissue types with different optical properties. Several types of reconstruction algorithms have been developed and verified experimentally. These investigations are pioneering work in the field of biomedical optics in Japan.     

初始电子密度对光学薄膜激光损伤机制的影响

光学元件的激光损伤问题是激光器件向高功率密度方向发展中必须认识和克服的问题.基于Forkker-Planck方程,研究了激光与材料相互作用时的雪崩电离机制、多光子电离机制以及联合两种机制的情况.雪崩电离的产生需要一定密度的初始自由电子存在,该自由电子可以是材料中原本就存在的,也可能是光电离产生的.着重分析了材料中的初始自由电子对材料电离机制的影响.结果表明,雪崩过程在激光作用一段时间后会达到一个稳定的电离阶段(以自由电子平均能量不随时间变化为特征,且此时雪崩电离为材料电离的主导机制),该时间与光电离速率、材料中初始自由电子密度有关.材料中的初始自由电子可以在一定程度上掩盖光电离的作用效果.     

Photon wave function formalism for analysis of Mach–Zehnder interferometer and sum-frequency generation

Biakynicki-Birula introduced a photon wave function similar to the matter wave function that satisfies the Schrödinger equation. Its second quantization form can be applied to investigate nonlinear optics at nearly full quantum level. In this paper, we applied the photon wave function formalism to analyze both linear optical processes in the well-known Mach–Zehnder interferometer and nonlinear optical processes for sum-frequency generation in dispersive and lossless medium. Results by photon wave function formalism agree with the well-established Maxwell treatments and existing experimental verifications.     

Integration of Chandrasekhar's integral equation

We solve Chandrasekhar's integration equation for radiative transfer in the plane-parallel atmosphere by iterative integration. The primary thrust in radiative transfer has been to solve the forward problem, i.e., to evaluate the radiance, given the optical thickness and the scattering phase function. In the area of satellite remote sensing, our problem is the inverse problem: to retrieve the surface reflectance and the optical thickness of the atmosphere from the radiance measured by satellites. In order to retrieve the optical thickness and the surface reflectance from the radiance at the top-of-the atmosphere (TOA), we should express the radiance at TOA “explicitly” in the optical thickness and the surface reflectance. Chandrasekhar formalized radiative transfer in the plane-parallel atmosphere in a simultaneous integral equation, and he obtained the second approximation. Since then no higher approximation has been reported. In this paper, we obtain the third approximation of the scattering function. We integrate functions derived from the second approximation in the integral interval from 1 to ∞ of the inverse of the cos of zenith angles. We can obtain the indefinite integral rather easily in the form of a series expansion. However, the integrals at the upper limit, ∞, are not yet known to us. We can assess the converged values of those series expansions at ∞ through calculus. For integration, we choose coupling pairs to avoid unnecessary terms in the outcome of integral and discover that the simultaneous integral equation can be deduced to the mere integral equation. Through algebraic calculation, we obtain the third approximation as a polynomial of the third degree in the atmospheric optical thickness.     

石墨烯超快动态光学性质

通过建立石墨烯的光学布洛赫方程, 研究了弱光场下的单层石墨烯超快动态光学性质. 理论研究表明在太赫兹辐射光场下由于泡利不相容和能量守恒原理使得石墨烯系统建立动态非平衡载流子并达到饱和的时间是20–200 fs, 能够在1 ps之内迅速产生光电流. 研究发现√2ev_F E₀ t<0 和ω 分别对应入射光的强度和频率, t为时间, v_F是石墨烯狄拉克点附近电子的费米速度. 研究发现光子能量?ω越大, 电极化强度以及光电流越强. 我们的理论研究结果与已有的众多实验结果一致, 表明石墨烯在超快动态光学领域尤其是太赫兹领域拥有重要的研究和应用价值.     

Thermal dissipation effects of the entangled photon generated by four-wave mixing process in a nonlinear ring resonator

We firstly analyze the thermal dissipation effects of the entangled photons generated by a nonlinear optical ring resonator. To obtain the corresponding equation of motion of the entangled photons generated by a four-wave mixing process within the system, we propose the Markov approximation to repel the reservoir operators. The system master equation in the interaction picture for both degenerate and non-degenerate cases is analyzed and obtained. The established system can be used to characterize the optimum entangled photons in some cases where the thermal dissipation effects may be introduced noise into the system. In this work, the entangled photons can be generated into two forms, firstly, the two entangled photon states is generated, the other, the four entangled photon states can be easily obtained. Results obtained have shown that the optimum entangled photon in term of entangled photon visibility can be compensated (i.e. unchanged) under thermal dissipation effects.     

Theoretical analysis of a coated single-mode fiber termination

The antireflection efficiency of a single layer coating in front of an abruptly terminated monomode optical fiber is treated analytically by means of an integral equation, that is appropriate to solve the corresponding boundary value problem. Both guided and radiation modes are taken into account, when describing the field inside the optical fiber region. Then the integral equation is solved approximately by a Neumann series procedure giving highly accurate results when the weakly guidance condition holds, which is a case of practical interest in the optical communications area. The reflection coefficient and the radiation pattern of this configuration are computed. Numerical results are given for several values of the parameters of the geometry under consideration.     

Thermal dissipation effects of the entangled photon generated by a nonlinear ring resonator

We firstly analyze the thermal dissipation effects of the entangled photons generated by a nonlinear optical ring resonator. To obtain the corresponding equation of motion of the entangled photons generated by a four-wave mixing process within the system, we propose the Markov approximation to repel the reservoir operators. The system master equation in the interaction picture for both degenerate and non-degenerate cases is analyzed and obtained. The established system can be used to characterize the optimum entangled photons in some cases where the thermal dissipation effects may introduce noise into the system. In this work, the entangled photons can be generated into two forms, firstly, the two entangled photon states are generated and, the other, the four entangled photon states, can be easily obtained. Results obtained have shown that the optimum entangled photon in terms of entangled photon visibility can be compensated (i.e. unchanged) under thermal dissipation effects.     

UV-B诱导的大豆愈伤组织超弱光子辐射的动力学分析

为了研究细胞超弱光子辐射的动力学特征及其所揭示的生物学意义,用20 μW/cm2UV-B辐射大豆愈伤组织2 h,测定停止辐射后4 d内大豆愈伤组织在LED光诱导下的延迟发光.通过建立延迟发光动力学方程和数学拟合得到了大豆愈伤组织超弱光子辐射中的延迟发光积分强度、初始光子数、衰减参数和自发发光,讨论了这些发光动力学参数的生物学意义.研究结果表明,在停止UV-B辐射后的4 d内,大豆愈伤组织的光诱导延迟发光服从双曲线弛豫.动力学分析发现,延迟发光积分强度和初始光子数随处理后时间的进行呈现波动变化,停止UV-B辐射后,自发发光和丙二醛（MDA）含量均呈现升高的趋势,在辐射后2 d附近达到峰值,此后同步下降.用延迟发光积分强度和自发发光的比值定义细胞的状态参量Q和序参量R,发现UV-B辐射后大豆愈伤组织细胞Q值或R值的变化反映了UV-B辐射对大豆愈伤组织细胞的损伤以及细胞的恢复过程.