This Volume 4767 of the conference proceedings contains 19 papers. Topics discussed include optical system, optical sensors, optical materials, opticaldesign and optical devices.
This Volume 4767 of the conference proceedings contains 19 papers. Topics discussed include optical system, optical sensors, optical materials, opticaldesign and optical devices.
In this paper, the design of a dual field-of-view optical system for 3-5 mum infra-red focal-plane arrays is described. Preliminary calculations are done to determine the first-order parameters of the narrow and the w...
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ISBN:
(纸本)0819445347
In this paper, the design of a dual field-of-view optical system for 3-5 mum infra-red focal-plane arrays is described. Preliminary calculations are done to determine the first-order parameters of the narrow and the wide-field modes. To achieve a switchable dual field-of-view system, two different optical configurations, one based on the axial motion of a lens group and the other based on a rotate-in motion of two separated lens groups, are studied and compared. Diffractive and conic surfaces are used to control the color and the monochromatic aberrations with less number of total lenses used. Paraxial and real-ray modelling of the Narcissus effect is described. It is shown that the rotate-in scheme achieves better optical performance in both the narrow and the wide-field modes. The axial-motion scheme suffers from poor lateral color in the wide-angle mode. The final opticaldesigns along with their aberrations curves and MTF plots are presented showing excellent performance.
We first consider the potential impact of a technology that could deliver polished, accurate aspheric surfaces in a routine and automated manner. We then summarise the technical challenge, and present an appraisal of ...
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ISBN:
(纸本)0819445347
We first consider the potential impact of a technology that could deliver polished, accurate aspheric surfaces in a routine and automated manner. We then summarise the technical challenge, and present an appraisal of the performance of the novel 'Precessions' process, which is a major advance in this direction. We outline the design concepts behind the productionized CNC polishing machines which executes the process, and then describe the progress developing strategies to preserve form when polishing ground surfaces, and to correct form on both pre-ground and polished surfaces. Particular consideration is given to resolving the inherent difficulties of control of centres on rotationally-symmetric parts. We then report on experimental results achieved with the machines. Finally, we present our programme to extend the control-algorithms to handle fully free-form surfaces, and draw conclusions about the effectiveness and generality of the 'Precessions' technique.
Results of measurements of the total hemispherical reflectance (THR), emissivity c and solar radiation absorption factor alpha(s) of the Al-Cr stray-light-absorptive coating are reported. This coating was designed to ...
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ISBN:
(纸本)0819445347
Results of measurements of the total hemispherical reflectance (THR), emissivity c and solar radiation absorption factor alpha(s) of the Al-Cr stray-light-absorptive coating are reported. This coating was designed to reduce the stray sunlight background in aerospace instruments. Generally, this problem arises when a density of instruments installed on the satellite is high and it is difficult to avoid getting to instrument the light reflected by neighboring devices. The THR, epsilon and alpha(s) measurement results are presented for 10 wavelengths within a range from. 400 to 927 nm, and also at 121.6 nm, the most intensive line of the solar UV spectrum, which is able to create considerable contribution to the detector noise in space devices. The goal of present experiments was to test an idea that by providing the electron scattering in the coating skin layer, it is possible to reduce the THR. To have the samples with increased electron scattering intensity, the samples of the Al-Cr coating were manufactured. As in the Al-Cr alloy the d-band of chromium electrons is located in the vicinity of the Fermi energy of Al, in this alloy a considerable electron scattering takes place. Therefore, within the skin layer of such coating, the electrons excited by photons transfer their energies and momenta to the lattice and other electrons instead of releasing the secondary photons. Hence, the reflectivity of the Al-Cr coating might be reduced. The prepared samples and performed experiments confirmed this assumption. According to the measurement results, the chromium appears to be an acceptable additional admixture to provide a further reflectivity reduction in the previously studied promising Al-N coating.
In order to produce an instrument or sensor design in the face of demanding environmental constraints of a spaceborne system, an integrated approach to sensor design has been developed that incorporates design tools f...
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ISBN:
(纸本)0819441554
In order to produce an instrument or sensor design in the face of demanding environmental constraints of a spaceborne system, an integrated approach to sensor design has been developed that incorporates design tools for: opticaldesign, mechanical design, structural, stray light and thermal analysis. This integrated approach can be extended to the entire payload design and its increased constraints.
Hybrid optics offer a valuable aberration correction tool for the lensdesigner. However, careful consideration must be given to the calculation of the optical performance during the design process, and to the practic...
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ISBN:
(纸本)0819441554
Hybrid optics offer a valuable aberration correction tool for the lensdesigner. However, careful consideration must be given to the calculation of the optical performance during the design process, and to the practical implementation of the elements if the potential benefits are to be realised in practice. optical performance can be accurately assessed by tracing multiple diffraction orders. It may be particularly important to utilise such a technique if, for example, the image-forming bundles sample a small number of diffractive zones. This situation is examined in detail.
The proceedings contained 20 papers from the journal on currentdevelopments in lensdesign and opticalengineering. The topics discussed included: optics for binocular telescopes;enhancements to the optimization proc...
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The proceedings contained 20 papers from the journal on currentdevelopments in lensdesign and opticalengineering. The topics discussed included: optics for binocular telescopes;enhancements to the optimization process in lensdesign;integrated opticaldesign and advanced opticaldesign for biochip scanning systems.
作者:
Thibault, SINO
Opt Engn Div St Foy PQ G1P 4S4 Canada
Generally, a spectrometer uses a diffraction grating to spread the spectral components of a light incident on the diffraction grating on a one-dimensional detector. The detector is composed of pixels linearly distribu...
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ISBN:
(纸本)0819441554
Generally, a spectrometer uses a diffraction grating to spread the spectral components of a light incident on the diffraction grating on a one-dimensional detector. The detector is composed of pixels linearly distributed along a line. However, the diffracted light is not spread linearly on the detector which means that the Wavelength on pixel I is not linearly correlated with the wavelength on pixel 2. The resolution is therefore not constant for all the spectral range of the spectrometer. To know which pixel corresponds to which wavelength, a nonlinear calibration process must be applied to get a linear relation between the diffracted light position and the wavelength of this light. The new spectrometer that we present uses a special lens configuration name F-sin(theta) lens to provide a linear relation in the image plane between the pixel position and the wavelength of the light. The f-sin(theta) characteristic is defined as the difference in percent between the design position of the wavelength in the image plane and its ideal position, if the lens is perfect. The characteristic of the lens used in the spectrometer is better than 0.1%. The concept can also be used for WDM and DWDM applications.
作者:
Thibault, SINO
Opt Engn Div St Foy PQ G1P 4S4 Canada
Introducing the desired amount of distortion in an optical system is possible and relatively straight forward for opticaldesigner. Known f-theta lenses used in laser scanner system is one of the most popular lenses o...
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ISBN:
(纸本)0819441554
Introducing the desired amount of distortion in an optical system is possible and relatively straight forward for opticaldesigner. Known f-theta lenses used in laser scanner system is one of the most popular lenses of this type. With the development of DWDM system, compact spectrometer and various grating based devices, the interest in solving optical problems with innovative opticaldesign has been a revival. On the other hand, it is possible to simplify considerably the task of the software by designing more sophisticated optical element. The F-sin(theta) lens is such a device which can be used in various grating based devices to improve the performance. This optical device is intended to provide a new lens or lens group which can be used with a diffraction grating to provide a linear output plane with the wavelength (lambda), but also with the order of diffraction (m), or with the grating spatial frequency, or with the inverse of the index of refraction (l/n). Based on theoretical consideration, we calculated which amount of distortion is desired to get linear output plane for a grating based device. We present singlet. achromatic doublet and mirror having this characteristic. These F-sin(theta) lenses present satisfactory distortion charateristic and have an improved correction for the curvature of image plane. F-sin(theta) lens will be also name F-lambda lens.
Over the years much time has been dedicated to improving lens optimisation routines. Most of the work has been upon the damped least squares (DLS) method. In this paper a number of theoretical and practical enhancemen...
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ISBN:
(纸本)0819441554
Over the years much time has been dedicated to improving lens optimisation routines. Most of the work has been upon the damped least squares (DLS) method. In this paper a number of theoretical and practical enhancements are presented. Some are new, others have already been published but never transposed into commercial software. These enhancements combine to allow the user to make more informed choices at every stage of an optimisation, and have now been incorporated into the widely used Winlens software package.
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