检索结果-内蒙古大学图书馆

current developments in optical design and engineering V

作者： Sinclair, R.Lawrence High, Martin Spar Aerospace Ltd. Hamilton ON Can

ISBN: (纸本)0819418994

Germanium (Ge) is the most widely used material in long wave infrared (LWIR) refractive telescopes due to its high index of refraction and very low dispersion characteristics. Unfortunately, germanium's absorption increases dramatically when operating in hot environments. Traditionally, the operating temperature of Ge is extended by doping to reduce the absorption coefficient's temperature dependence. However, depending upon the optical design form, transmission losses attributed to an operating temperature rise of 40 degrees, may still be as high as 5 to 15 percent. When such absorption losses are not tolerable, alternative materials such as ZnSe, Amtirl, and GaAs can be considered. In this paper a series of case studied is presented to compare the predicted performance of conventional Ge dominated designs with lenses composed almost entirely of these alternative materials. Fabrication and production cost issues are compared along with the utilization of hybrid refractive/diffractive optical elements.

关键词： Telescopes

来源：评论

学校读者我要写书评

暂无评论

Matrix method for optomechanical tolerancing of finite conjugate optical imaging systems

Matrix method for optomechanical tolerancing of finite conju...

引用

current developments in optical design and engineering V

作者： Penkethman, John A. Electroglas Inc. Gilroy CA USA

ISBN: (纸本)0819418994

In any optical imaging system, tilting and decentering of optical components will cause the relationship between the object and image to change. Many precision imaging systems require the image to have a fixed relationship to the object within a certain tolerance. To obtain an object-to-image relationship within a specified tolerance, each of the possibly many components must in turn be positioned within certain tolerances. The allowable tilt and decenter of each component depends upon the sensitivity of the image position to that component's motion. This sensitivity is often referred to as a structural influence coefficient. A method is presented for the derivation and calculation of structural influence coefficients for finite conjugate optical imaging systems. A special differential rotation operator is introduced to model tilts of optical components. The method most easily results in numerical coefficients with the use of a personal computer and almost any common mathematical software package.

关键词： optical systems

来源：评论

学校读者我要写书评

暂无评论

Athermalized color correction in glass-liquid optical systems

Athermalized color correction in glass-liquid optical system...

引用

current developments in optical design and engineering V

作者： Abramov, Alexander P. Petrova, Maria V. Tolstoy, Michael N. Robb, Paul N. Sigler, Robert D. S.I. Vavilov State Optical Inst. St. Petersburg Russia

ISBN: (纸本)0819418994

The incorporation of abnormal dispersion liquids into an optical design can result in significant performance advantages. However, the large thermal coefficient of refractive index which is common to all liquids (dn/dT) can complicate the athermalization of these designs. One method is to use two different liquids to form both positive and negative liquid lens elements which balance each other thermally while maintaining color correction. The success of this approach is dependent on the proper selection of materials, and on a detailed knowledge of the wavelength dependence of the refractive index thermal coefficients. The thermal dependence of refractive index and dispersion in the visible spectral region for a number of liquids was investigated. A correlation between the refractive index thermal coefficient (dn/dT) and abnormal dispersion was found to exist in a majority of liquids. The optical property measurements were made at the Vavilov State optical Institute, St. Petersburg, Russia in collaboration with the Lockheed Palo Alto Research Laboratory, Palo Alto, California.

关键词： optical systems

来源：评论

学校读者我要写书评

暂无评论

optical components in polymers

Optical components in polymers

引用

current developments in optical design and engineering V

作者： Schoesser, Alexander Knoedler, Bengt Tschudi, Theo T. Frank, Werner F. Stelmaszyk, Angelika Muschert, D. Rueck, Dorothee M. Brunner, Stefan Pozzi, Fabio Morasca, Salvatore De Bernardi, Carlo S. Technische Hochschule Darmstadt Darmstadt Ger

ISBN: (纸本)0819418994

Samples of PMMA [Poly-(Methyl-Meth-Acrylate)] were modified by ionizing radiation (especially UV-radiation) in order to generate regions of increased refractive index. These waveguiding structures were used to build optical power splitters and optical polarizers simply by varying the exposure time. The refractive index profile and the variation in thickness of the waveguides for different exposure times were observed. Also the cut-off-wavelength and the spectral absorption behavior for different exposure times were measured. The compaction at the surface was used to build up diffraction gratings with grating constants of 4 micrometer to 20 micrometer. By annealing the samples the diffraction efficiency was increased.

关键词： optical devices

来源：评论

学校读者我要写书评

暂无评论

design of laser focusing system for laser-microbeam instrument

Design of laser focusing system for laser-microbeam instrume...

引用

current developments in optical design and engineering V

作者： Zhu, Yanbin Ma, Junfu South China Normal Univ. Guangzhou Guangdong China

ISBN: (纸本)0819418994

Recently the laser microbeam instrument has been used for wider applications in biological science and medicine. A key problem of the laser microbeam instrument is designing the laser focusing system for getting a focal spot size of less than 1 micrometer. This paper presents a new laser focusing system which is composed of a spatial filter and an 80× focusing objective lens. The 80× focusing objective lens was designed as a double reflective sphere type. Using this focusing system, the laser microbeam instrument has gotten a focal spot size of less than 0.5 - 1 micrometer. The focal spot size depends on the pinhole diaphragm diameter of the spatial filter. Different pinhole diaphragm diameters could produce different focal spots that are given in the end of this paper.

关键词： optical instruments

来源：评论

学校读者我要写书评

暂无评论

New type of prismatic telescope

New type of prismatic telescope

引用

current developments in optical design and engineering V

作者： Xu, Fuyun Liu, Xin Yu, Chengxin Wu, Qingsheng Zhang, Ying Shandong Architectural Engineering Inst. Shandong Jinan China

ISBN: (纸本)0819418994

In this article we have designed a new type of prismatic telescope which can be used to amplify the divergence of the laser beam. Theoretical analysis and computer analog indicate that the divergence multiplication factor is independent of the distance between the prismatic telescope and the waist of the laser beam, and the original divergence of the laser beam in 20 mrad, the laser beam as it passes through the prismatic telescope is still Gaussian beam. We have made and measured the prismatic telescope and found the result agrees with our theoretical analysis.

关键词： Telescopes

来源：评论

学校读者我要写书评

暂无评论

High-optical-quality cryogenic hollow retroreflectors

High-optical-quality cryogenic hollow retroreflectors

引用

current developments in optical design and engineering V

作者： Lyons III, James J. Hayes, Patricia A. NASA Goddard Space Flight Cent. Greenbelt MD USA

ISBN: (纸本)0819418994

The Cassini mission to Saturn will contain the CIRS instrument which is currently being developed and assembled at the Goddard Space Flight Center. The CIRS instrument contains two science interferometers that operate in the mid and far infrared regions of the spectrum and one reference interferometer which operates in the visible. The heart of each of the interferometers is a series of hollow glass retroreflectors (cube corners) and hollow dihedrals. The hollow retroreflectors are constructed of individual facets of zerodur glass which are bonded 90 degrees to each other to sub arc-second accuracies. They are then coated with a reflective overcoat to meet the wavelength requirements. The effort at Goddard resulted in the development of retroreflectors that not only performed well at ambient temperatures, but also retained a wavefront error of approximately 2 waves p-v with a maximum beam deviation of 15 arc seconds at a temperature of 170 degrees kelvin or below. Also developed at GSFC is a successful means of mounting the retroreflectors on a fixed zerodur mount to allow cooling them down to these temperatures without introducing any added stresses that are not already present in the unmounted retroreflectors.

关键词： optical instruments

来源：评论

学校读者我要写书评

暂无评论

ISDN LOOP EXTENSION USING A MID-SPAN AMPLIFIER

引用

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 1995年第3期8卷 219-224页

作者： ERKER, GJ DODDS, DE KRZYMIEN, WA David E. Dodds was born in Saskatoon Canada in 1945. He received the B. Eng. and MSc. degrees from the University of Saskatchewan in 1966 and 1968 respectively. He worked with Bell Northern Research (Ottawa) on PBX design in 1969 1972 and 1978. Since 1969 he has been with the University of Saskatchewan where he is currently Professor of Electrical Engineering. He teaches courses in electronics and communications and also presents short courses on the fundamentals of telephony. Current research interests are in data transmission signal processing architecture and frame synchronization for PCM and spread spectrum systems. He has been granted five patents relating to commercial products in delta-modulation telephone line interfacing and computer data transmission. In 1986 he was on sabbatical leave at BNR Inc. and worked with an ANSI committee on the standardization of FDDI-II a combined voice and data system. Mr. Dodds is a Registered Consulting Engineer in Saskatchewan. Witold A. Krzyden received his MSc. (Eng.) and Ph.D. degrees (both in Electrical Engineering) in 1970 and 1978 respectively from the Poznan Technical University in Poznan Poland. He was awarded the Minister's of Science and Technology Prize of Excellence for his Ph.D. thesis. From 1970 to 1978 he was a Research Engineer and Teaching Assistant and then from 1978 to 1980 an Assistant Professor of Electrical Engineering at the Poznan Technical University. In 1980 he won a Dutch Government Research Fellowship at the Twente University of Technology in Enschede the Netherlands for the year of 1980/1981. In the following year of 1981/82 he was a Research Assistant Professor there. From 1982 to 1986 he was an Assistant Professor of Electrical Engineering at Lakehead University in Thunder Bay Ontario Canada. In 1986 he joined the Univeristy of Alberta and Alberta Telecommunications Research Centre (now Telecommunications Research Laboratories or TRLabs) as an Associate Professor of Electrical Engineering. Currently he is a Professor of E

The 5.5 km range of the basic rate ISDN loop has been extended by using a negative impedance amplifier and by using a 2 wire/4 wire (2w/4w) amplifier. The negative impedance amplifier extends the range of the loop by 1.0 km, whereas the 2w/4w amplifier extends the range by 1.5 km at the expense of increased complexity. As part of the amplifer design, a resistor/capacitor network has been developed which closely matches the characteristic impedance of telephone cable. Error rate tests have been conducted using various lengths of cable and an operating ISDN line.

关键词： ISDN PHYSICAL LAYER BASIC RATE LOOP RANGE EXTENSION

来源：评论

学校读者我要写书评

暂无评论

current developments in optical design and optical engineering IV

Current Developments in Optical Design and Optical Engineeri...

引用

current developments in optical design and optical engineering IV 1994

The proceedings contain 45 papers. The topics discussed include: optical design of a two-mirror asymmetrical reshaping system and its application in superbroadband color center lasers;refractive indices of liquids in the infrared spectral region;stability of the optical properties of abnormally dispersive liquids;optical performance of axial gradient and aspheric surface lenses: study and analysis;multilevel Fresnel zone lenses capable of being fabricated with only one binary mask;computer-generated diffractive optical elements for optical interconnections: design and validation codes;and nonphotolithographic fabrication of large computer-generated diffractive optical elements.

关键词：

来源：评论

学校读者我要写书评

暂无评论

COMPUTER-GENERATED DIFFRACTIVE optical-ELEMENTS FOR optical INTERCONNECTIONS - design AND VALIDATION CODES 4

COMPUTER-GENERATED DIFFRACTIVE OPTICAL-ELEMENTS FOR OPTICAL ...

引用

Conference on current developments in optical design and optical engineering IV

作者： DIMARTINO, P PERRONE, G MONTROSSET, I POLITECN TORINO DIPARTIMENTO ELETTR I-10129 TURIN ITALY

ISBN: (纸本)0819415871

In this paper we discuss the design of Diffractive optical Elements that can be used for optical interconnections. Q uite general computer programs have been realized for the design and the validation of such optical elements. As examples, in the paper we discuss the design of a 1 to 3, a 1 to 5 and a 1 to 4 interconnections, workingeither in reflection or in transmission.

关键词： Diffractive optical elements optical design Wavefronts optical interconnects optical components Reflection Reflectivity Computing systems Network architectures Resistors

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：