Geometrical-transformation approach to optical two-dimensional beam shaping: comment

I show that the research reported by Arieli et al. [Appl. Opt. 86, 9129 (1997)] has two serious mistakes: One is that an important factor is lost in the formula used in that study to determine the x-direction coordinate transformation; the other is the conclusion that the geometrical-transformation approach given by Arieli et al. can provide a smooth phase distribution. A potential research direction for obtaining a smooth phase distribution for a generic two-dimensional beam-shaping problem is stated. (C) 1998 Optical Society of America.

Approximate analytical description for fundamental-mode fields of graded-index fibers: Beyond the Gaussian approximation

An approximate analytical description for fundamental-mode fields of graded-index fibers is explicitly presented by use of the power-series expansion method, the maximum-value condition at the fiber axis, the decay properties of fundamental-mode fields at large distance from the fiber axis, and the approximate modal parameters U obtained from the Gaussian approximation. This analytical description is much more accurate than the Gaussian approximation and at the same time keep the simplicity of the latter. As two special examples, we present the approximate analytical formulas for the fundamental-mode fields of a step profile fiber and a Gaussian profile fiber, and we find that they are both highly accurate in the single-mode range by comparing them with the corresponding exact solutions.

Corrections to the paraxial approximation solutions in transversely nonuniform refractive-index media

The coupled differential recurrence equations for the corrections to the paraxial approximation solutions in transversely nonuniform refractive-index media are established in terms of the perturbation method. All the corrections (including the longitudinal field corrections) to the paraxial approximation solutions are presented in the weak-guidance approximation. As a concrete application, the first-order longitudinal field correction and the second-order transverse field correction to the paraxial approximation of a Gaussian beam propagating in a transversely quadratic refractive index medium are analytically investigated. (C) 1999 Optical Society of America [S0740-3232(99)00310-5].

Prism coupling of ultrashort light pulses into waveguides

We discuss coupling of ultrashort light pulses into waveguides by use of a prism waveguide coupler configuration. Theoretical analysis indicates that an extra loss induced by the short coherence times of ultrashort pulses, which has a strong effect on the reflected light and the optimum coupling condition, appears in the waveguide. Numerical simulations show that the reflectance strongly depends on the coherence times of ultrashort pulses. A method for realizing optimum coupling by compensating for the extra loss is proposed as well in this paper. A preliminary experiment of employing ultrashort pulses with different coherence times was carried out, and good agreement between theory and experiment was obtained. (c) 2006 Optical Society of America.

Spectral shaping of femtosecond pulses with a prism-waveguide coupler

We report a novel technique for spectral shaping of femtosecond pulses employing a prism-waveguide coupler (PWC). It is demonstrated that the PWC is capable of producing a frequency-dependent loss with greater attenuation at the peak of the spectrum profile of femtosecond pulses than in the wings, which is especially useful for compensation for gain narrowing in most chirped-pulse amplification laser systems.

Construction of the refractive index profiles for few-mode planar optical waveguides

We present a nondestructive technique to predict the refractive index profiles of isotropic planar waveguides, on which a thin gold film is deposited to as the cladding. The negative dielectric constant of the metal results in significant differences of effective indices between TE and TM modes. The two polarized modes and a surface plasmon resonance (SPR) with abundant information of the surface index can be used to construct the refractive index profiles of single-mode and two-mode waveguides at a fixed wavelength. (c) 2005 Elsevier B.V. All rights reserved.

System error removal and structure optimization based on Fizeau interferometer

In the process of interferometric testing, the measurement result is influenced by the system structure, which reduces the measurement accuracy. To obtain an accurate test result, it is necessary to analyze the test system, and build the relationship between the measurement error and the system parameters. In this paper, the influences of the system elements which include the collimated lens and the standard surface on the interferometric testing are analyzed, the expressions of phase distribution and wavefront error on the detector are obtained, the method to remove some element errors is introduced, and the optimization structure relationships are given. (C) 2006 Elsevier GmbH. All rights reserved.

PIXE and ICP-AES analysis of early glass unearthed from Xinjiang (China)

Early glasses (about 1066 BC-220 AD) unearthed from Xinjiang of China were chemically characterized by using PIXE and ICP-AES. It was found that these glasses were basically attributed to PbO-BaO-SiO2 system, K2O-SiO2 system, Na2O-CaO-SiO2 system and Na2O-CaO-PbO-SiO2 system. The results from the cluster analysis showed that some glasses had basically similar recipe and technology. The PbO-BaO-SiO2 glass and the K2O-SiO2 glass were thought to come from the central area and the south of ancient China, respectively. The part of the Na2O-CaO-SiO2 glass (including the Na2O-CaO-PbO-SiO2 glass) might be imported from Mesopotamia, while the other part might be locally produced. (c) 2005 Elsevier B.V. All rights reserved.

Origin of Chinese ancient glasses;study on the earliest Chinese ancient glasses

The earliest Chinese ancient glasses before the West Han Dynasty (200 BC) from different regions are studied. The glass samples were unearthed from Hunan, Hubei, Yunnan, Sichuan, Guizhou, Guangdong and Xinjiang of China. The chemical composition of these glasses samples is analyzed by proton induced X-ray emission (PIXE) technique, energy dispersive X-ray fluorescence (EDXRF) method and inductively coupled plasma atomic emission spectrometry (ICP-AES). It is shown that the glass chemical compositions belong to barium-lead silicate BaO-PbO-SiO2, potash soda lime silicate K2O (Na2O)-CaO-SiO2 (K2O/Na2O > 1), soda potash lime silicate Na2O (K2O)-CaO-SiO2 (K2O/Na2O < 1) and potash silicate K2O-SiO2 glass systems, respectively. The origins of the earliest Chinese ancient glasses are discussed from the archaeological and historical points of view. These four types of Chinese ancient glasses were all made in Chinese territory using local raw materials. The glass preparation technology was related to the Chinese ancient bronze metallurgy and proto-porcelain glaze technology. The glass technology relationship between the East and the West is analyzed at the same time.

一批中国古玻璃化学成分的质子激发X射线荧光分析

质子激发X射线荧光(proton induced X-ray emission，PIXE)技术是一种高灵敏度、非破坏性、多元素定量测定的分析方法。采用外束PIXE技术对内蒙古地区和博山出土的一批古代玻璃的化学成分进行了定量测定。结果表明：内蒙古地区出土的玻璃中，西周时期的玻璃珠是含有少量K2O和CaO助熔剂的釉砂，其主要成分为SiO2；汉代的玻璃珠属于PbO—SiO2玻璃；多数元代的玻璃制品和部分北魏时期的玻璃珠属于K2O—CaO—SiO2玻璃。博山出土的元末明初的玻璃基本为KzO-CaO—SiO2系玻璃

一批中国古代镶嵌玻璃珠化学成分的检测报告

结合外束质子激发X荧光（proton induced X-ray emission,PIXE）和能量色散X射线荧光（energy dispersive X-ray emission,EDXRF）分析技术,对中国新疆、湖北、四川、广东出土的古代镶嵌玻璃珠的化学成分进行了检测.结果表明：新疆拜城克孜尔墓地出土的西周-春秋时期镶嵌玻璃珠为CaO-MgO-SiO2玻璃,战国时期中国境内的PbO-BaO-SiO2和Na2O-CaO-SiO2镶嵌玻璃珠是同时存在的.本文亦对相关问题进行了一些讨论,并提出了部分今后的工

基于多元统计分析方法对一批中国南方和西南地区的古玻璃成分的研究

采用多元统计方法对四川、重庆、贵州、广西、广东地区出土的100余个古玻璃样品的化学成分数据进行了分析处理。结果表明：中国南方和西南地区的古玻璃制品主要由具有中国特色的铅钡硅酸盐玻璃和钾硅酸盐玻璃组成，可细分为五大系统类别：K2O-CaO（～10wt％）-SiO2系统、K2O-SiO2系统、PbO-BaO-SiO2系统、PbO（～25wt％）-BaO-SiO2系统、CaO-PbO（～40wt％）-BaO—SiO2系统。用因子分析探讨了我国汉代南方和西南地区的玻璃本地生产情况，表明该地区在汉代已经拥有自主生产