Use of Dirac matrices in polarization optics

Several matrix methods have been developed for studying polarization properties of light. Jones was the first to apply the matrix method to the study of polarization optics. In Jones matrix formalism the polarized wave field is represented by 2-element column matrix known as Jones Vector and the polarization device encountered by light is represented by a 2×2 matrix, known as the characteristic Jones matrix of the device. Mueller introduced a new matrix method where the wave field is represented by a 4-dimensional vector. The elements of the vector are the Stokes parameters of the beam. In Mueller matrix formalism the optical device is represented by a 4×4 real matrix known as ‘Mueller Matrix’ of the device. The use of coherency matrix also proves to the useful in the study of partially polarized light. Pauli spin matrices have been used to unify the different matrix treatments of polarization optical phenomena. The present article is an attempt to unify the analysis of polarization phenomena using Dirac matrices used by Dirac in quantum mechanics. We have however redefined the set of Dirac matrices in terms of the Kronecher product of Pauli spin matrices.     

Use of a microelectromechanical mirror for adaptive optics in the human eye

Ophthalmic instrumentation equipped with adaptive optics offers the possibility of rapid and automated correction of the eye's optics for improving vision and for improving images of the retina. One factor that limits the widespread implementation of adaptive optics is the cost of the wave-front corrector, such as a deformable mirror. In addition, the large apertures of these elements require high pupil magnification, and hence the systems tend to be physically large. We present what are believed to be the first closed-loop results when a compact, low-cost, surface micromachined, microelectromechanical mirror is used in a vision adaptive-optics system. The correction performance of the mirror is shown to be comparable to that of a Xinetics mirror for a 4.6-mm pupil size. Furthermore, for a pupil diameter of 6.0-mm, the residual rms error is reduced from 0.36 to 0.12 microm and individual photoreceptors are resolved at a pupil eccentricity of 1 degrees from the fovea.     

小波域中的维纳滤波在综合脉冲星时算法中的应用

脉冲星自转非常稳定，可用作时间标准. 然而由单脉冲星定义的脉冲星时受多种噪声源的影响，其频率稳定度还不够好，因此可采取对多颗脉冲星定义的脉冲星时进行综合的方法来削弱各噪声源的影响，以提高脉冲星时的稳定度. 不同的脉冲星有着各自不同的自转频率，在不同频率段所受噪声的影响也不同，应用小波分析的方法对脉冲星时做综合，可以兼顾脉冲星时的长期与短期稳定度，在不同的频率范围取不同的权值以达到更好的结果；脉冲星的计时残差是由计时参考的原子时的误差和脉冲星计时误差两部分引起的，用维纳滤波的方法可以将两者分开，并主要以消除掉参考钟误差后的残差为计时残差实现对脉冲星计时的综合. 在这两种方法的基础上，提出一种基于小波域中的维纳滤波方法，利用小波独有的特性和维纳滤波最小误差估计的优点，更有效地消除噪声对脉冲星时的影响. 实验结果表明，该方法可以有效降低脉冲星计时残差中的噪声影响.     

A novel scheme of optical Meyer wavelet filter based on time lenses in nonlinear multi-span optics fiber communication system

In this work, a novel scheme to realize optical Meyer wavelet filter based on time lenses and Mach–Zehnder modulators in optical domain was proposed and the transfer functions of Meyer wavelet decomposition and reconstruction processed in frequency domain were derived to realize Meyer wavelet de-noising for optical signal. The filter could be used to reduce the nonlinear noise induced by the interaction of EDFA’s ASE noise, fiber’s dispersion and nonlinearity in high bit rate multi-span optical communication systems without photo-electric conversion. The bit error rate curves of the optical bit sequence without and with optical Meyer wavelet filter were plotted to show the effectiveness of the optical Meyer wavelet filter, which can achieve better result and improve the optical communication quality in dispersion compensation links.     

光纤中的集成光学与离散光学

光纤集成光学和离散光学有望成为光子学集成的一个新分支。这种集成技术可以通过离散的方法方便地在一根光纤中控制和操纵光波,也为集成光学与离散光学的研究提供了一个灵活方便的平台,为微光子器件和系统集成提供了一种有效的方法和手段。文章简要总结了在光纤内实现光学器件集成和微光学系统集成的主要思想和关键技术,探讨了离散光学需要考虑的核心内容,为该方向的进一步发展提供了若干前期的研究基础。     

Use of the poincare sphere in polarization optics and classical and quantum mechanics. Review

The method of the Poincaré sphere, which was proposed by Henri Poincaré in 1891–1892, is a convenient approach to represent polarized light. This method is graphical: each point on the sphere corresponds to a certain polarization state. Apart from the obvious representation of polarized light, the method of the Poincaré sphere permits efficient solution of problems that result from the use of a set of phase plates or a combination of phase plates and ideally homogeneous polarizers. Recently, to calculate the geometric phase (which is often called the Berry phase) in polarization optics and quantum and classical mechanics, the method of the Poincaré sphere has drawn much attention, since it allows us to carry out these calculations very efficiently and intuitively using the solid angle resting, on a closed curve on the Poincaré sphere that corresponds to the change in the state of light polarization or in the state of spin of an elementary particle or its orientation in space from the viewpoint of systems in classical mechanics. The review considers papers on the above problems. Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 3, pp. 265–307, March. 1997.     

Use of steel substrates in diffractive optics: Near field of high surface quality steel tape gratings

Steel tape is used in optical applications due to its mechanical properties. However, roughness of steel surfaces affects to wave propagation. The effect can be observed using diffraction gratings with low periods. In such a case, self-images of the grating appear at certain periodic distances from the grating (Talbot planes). When standard steel is used, the contrast of Talbot self-images strongly decreases with the distance from the grating. In this work, we prove that controlling the surface quality of steel, it is possible to improve its optical behavior and, as a consequence, high quality surface steel represents a good choice for diffractive optics when the use of chrome-on-glass masks is not indicated. As an example, we have manufactured a diffraction grating over a high quality steel surface by means of an ablation process with a nanosecond pulsed laser. The contrast of the self-images for these gratings decreases very slowly with the distance, in comparison with the self-images obtained with standard steel tape gratings.     

Adaptive optics in astronomy

Since Galileo’s first observations in 1609, telescopes have grown dramatically in size. Larger telescopes collect more light, allowing astronomers to detect fainter sources and to look further back in time towards the birth of the universe. The angular resolution of these telescopes, however, has been limited by turbulence in the earth’s atmosphere. This limitation can be dramatically reduced with the use of adaptive optics (AO) to measure and correct the blurring introduced by atmospheric turbulence. AO is now routinely used for science observations on the world’s largest telescopes and is providing a much more detailed view of our universe.     

Coherent states in optics

An approach has been developed with the use of coherent states for constructing wavelets based on spiral light beams.     

Symmetry in Lie optics

Optical systems produce nonlinear canonical transformations in optical phase space. Free propagation in a homogeneous medium has Euclidean symmetry and dynamical algebras under the Poisson-Lie bracket. Refracting interfaces between homogeneous media exhibit invariants; in particular, a spherical surface possesses an so(3) symmetry algebra which allows the recursive computation of its aberration coefficients to arbitrarily high order. We present explicit results for aberration order nine.     

Quantum correlations in optics

In many nonlinear optical problems, for example in down-conversion and four-wave mixing, the photons are generated in pairs. The strong correlation between the photons in a pair, characterized by either the correlations between operators corresponding to observables associated with individual photons, or the correlated state describing the two photons, may lead to various nonclassicalities. We discuss some of these nonclassical effects and their experimental demonstrations in nonlinear optical processes     

Phase problem in optics

The problem of reconstructing a coherent monochromatic field from its energy characteristics is considered. A comparative analysis is made of one- and two-dimensional phase problems. It is shown that a substantial role is played in the two-dimensional case by the vortical properties of the optical-energy flux vector. The results of computer and physical experiments are reported.Optics and Spectroscopy Division, Lebedev Physics Institute. Translated from Preprint No. 93 of the Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow, 1990.     

HMO in geometrical optics

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关联光学新进展

文章综述了利用光学自发参量下转换过程产生的纠缠双光子态和热光源的空间关联性,实现“鬼”成像、“鬼”干涉、亚波长干涉和非定域双缝干涉等实验的研究进展,以及其中涉及的争论问题.     

Fiber optics in japan

This paper describes the recent progress in research and development of fiber optics in Japan. A review is presented of recent developments in fiber manufacturing, cabling, and fiber splicing. Experimental results are given for an optical communication system with optoelectronic components. Theoretical analysis and fundamental experiments are not included, nor are research activities in such devices as lasers or in such applications as those in medical fields. Transmission characteristics of optical fibers—in particular loss and pulse spreading—are assessed from the viewpoint of their structures. Various methods of fiber strengthening and structuring cables are described from the viewpoint of mechanical strength. Coupling efficiencies of detachable connectors and methods of permanent fiber splicing are described. Experimental results on optical fiber communication systems are presented and coupling techniques between a light source and an optical fiber are described.     

Fiber optics in japan

Abstract

This paper describes the recent progress in research and development of fiber optics in Japan. A review is presented of recent developments in fiber manufacturing, cabling, and fiber splicing. Experimental results are given for an optical communication system with optoelectronic components. Theoretical analysis and fundamental experiments are not included, nor are research activities in such devices as lasers or in such applications as those in medical fields. Transmission characteristics of optical fibers—in particular loss and pulse spreading—are assessed from the viewpoint of their structures. Various methods of fiber strengthening and structuring cables are described from the viewpoint of mechanical strength. Coupling efficiencies of detachable connectors and methods of permanent fiber splicing are described. Experimental results on optical fiber communication systems are presented and coupling techniques between a light source and an optical fiber are described.     

HMO in nonlinear optics

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关联光学新进展

文章综述了利用光学自发参量下转换过程产生的纠缠双光子态和热光源的空间关联性,实现"鬼"成像、"鬼"干涉、亚波长干涉和非定域双缝干涉等实验的研究进展,以及其中涉及的争论问题.