A miniaturized instrument for systematic planetary mineralogy is presented, and the opticaldesign of the component parts is discussed. The instrument combines the following capabilities: wide field color imaging, con...
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ISBN:
(纸本)0819445347
A miniaturized instrument for systematic planetary mineralogy is presented, and the opticaldesign of the component parts is discussed. The instrument combines the following capabilities: wide field color imaging, confocal imaging at two different resolution/range levels, reflectance spectroscopy in the 400-2500 nm region with a resolution of 10 nm, and Raman spectroscopy over 4000 cm(-1) with an average resolution of 3.3 cm(-1). The instrument can also serve as an expandable platform for adding fluorescence spectroscopy, or for examining samples from a distance of several meters while using the same spectrometer.
We have developed a new method other than traditional technique based on ray tracing and optimization algorithm to design arbitrary aspherics. Analytic definition of the aspheric surfaces is done away with and numeric...
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ISBN:
(纸本)0819445347
We have developed a new method other than traditional technique based on ray tracing and optimization algorithm to design arbitrary aspherics. Analytic definition of the aspheric surfaces is done away with and numerical solution of nonlinear difference equations called Aspheric Intrinsic Equations (AIE) is implemented instead. Simulation results compared with traditional opticaldesign software are presented, which prove that this new method is more effective and reliable in designing aspheric surfaces.
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.
A method for computing the polychromatic MTF of hybrid refractive - diffractive elements is described taking into consideration the effects of not only the primary diffraction order but also the effects of additional ...
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ISBN:
(纸本)0819445347
A method for computing the polychromatic MTF of hybrid refractive - diffractive elements is described taking into consideration the effects of not only the primary diffraction order but also the effects of additional parasitic diffraction orders. The results of this approach are compared with the more conventional single order calculation and with actual measured performance. For certain markets and applications the cost of infrared lenses are critical in order to achieve customer expectations. Two possible methods of realising this requirement are the use of moulded optics or the use of multiple kinoform optics with no refractive power. Examples of such lenses are given along with discussion of the merits and limitations that each approach entails.
Several types of telescopes are used for free space telecommunications. The most common are Cassegrain and Gregorian telescopes. The main difference between Cassegrain and Gregorian optical systems is that Gregorian t...
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ISBN:
(纸本)0819445347
Several types of telescopes are used for free space telecommunications. The most common are Cassegrain and Gregorian telescopes. The main difference between Cassegrain and Gregorian optical systems is that Gregorian telescopes employ a concave secondary mirror located beyond the focus of the primary mirror. This results in longer tube lengths, as the distance between mirrors is slightly more than the sum of their focal lengths, which is the reason Cassegrain systems are the most common. In addition, Gregorian telescopes produce an upright image, while Cassegrain telescopes produce an inverted image.
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.
Helicopter mounted optical systems require compact packaging, good image performance (approaching the diffraction-limit), and must survive and operate in a rugged shock and thermal environment. The always-present requ...
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ISBN:
(纸本)0819445347
Helicopter mounted optical systems require compact packaging, good image performance (approaching the diffraction-limit), and must survive and operate in a rugged shock and thermal environment. The always-present requirement for low weight in an airborne sensor is paramount when considering the optical configuration. In addition, the usual list of optical requirements which must be satisfied within narrow tolerances, including field-of-view, vignetting, boresight, stray light rejection, and transmittance drive the opticaldesign. It must be determined early in the engineering process which internal optical alignment adjustment provisions must be included, which may be included, and which will have to be omitted, since adding alignment features often conflicts with the requirement for optical component stability during operation and of course adds weight. When the system is to be modular and mates with another optical system, a telescope designed by different contractor in this case, additional alignment requirements between the two systems must be specified and agreed upon. Final delivered cost is certainly critical and "touch labor" assembly time must be determined and controlled. A clear plan for the alignment and assembly steps must be devised before the opticaldesign can even begin to ensure that an arrangement of optical components amenable to adjustment is reached. The optical specification document should be written contemporaneously with the alignment plan to insure compatibility. The optics decisions that led to the success of this project are described and the final opticaldesign is presented. A description of some unique pupil alignment adjustments, never performed by us in the infrared, is described.
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.
The paper deals with the description of a simulation procedure for the design and the optimisation of tunable multi-section distributed Bragg reflector (DBR) lasers. In particular a special attention is dedicated to t...
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ISBN:
(纸本)0819451002
The paper deals with the description of a simulation procedure for the design and the optimisation of tunable multi-section distributed Bragg reflector (DBR) lasers. In particular a special attention is dedicated to the design of two-section DBR lasers with operating wavelengths matching the ITU frequency standard grid only by grating current tuning. To our knowledge this is the first time that by a proper design procedure this condition has been satisfied.
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