Nowadays most industrial and laboratory motion measuring equipment makes use of optical encoders to measure rotation and linear displacements with sub-micrometrical resolution. In this work we introduce a new design o...
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ISBN:
(纸本)9780819468154
Nowadays most industrial and laboratory motion measuring equipment makes use of optical encoders to measure rotation and linear displacements with sub-micrometrical resolution. In this work we introduce a new design of an optical encoder based on a non diffractive beam, a binary amplitude grating and a monolithic photodetector. Two theoretical models of the system are proposed and implemented to obtain numerical results. The performance of the design is also investigated through experimental measurements. Finally, the experimental results are compared with the models predictions.
LITE (Lidar In-space Technology Experiment) is a Langley Research Center project which will provide engineering data that can be used for future space-based lidar systems. The optical system consists of three science ...
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LITE (Lidar In-space Technology Experiment) is a Langley Research Center project which will provide engineering data that can be used for future space-based lidar systems. The optical system consists of three science channels (the 355 nm PMT, the 532 nm PMT, and the 1064 nm APD channels) and one active alignment channel (the 532 nm QUAD channel) as aft optics to a Ritchey Chretien telescope. The purpose of this paper is to present the results of a study done to generate a tolerance budget for LITE using a combination of manual and Monte Carlo tolerancing techniques using the SYNOPSYStm optical analysis program.
A baseline design for NASA's Terrestrial Planet Finder Coronagraph (TPFC) starlight suppression system (SSS) is described. The design is based on a 8×3.5m elliptical aperture telescope leading to terrestrial ...
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A baseline design for NASA's Terrestrial Planet Finder Coronagraph (TPFC) starlight suppression system (SSS) is described. The design is based on a 8×3.5m elliptical aperture telescope leading to terrestrial planet detection at a minimum angle of ∼4λ/D. The design accommodates classical Lyot coronagraph as well as shaped pupil approaches and includes separate optical paths for two polarizations each with its own deformable mirror control. Critical design challenges and trades are described.
A new method for correcting comatic aberration in holographic opticalsystems which uses constant optical path(COP) has been developed. The sum ofthe optical path lengths from an object wavefront to an image wavefront ...
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ISBN:
(纸本)0819403954
A new method for correcting comatic aberration in holographic optical
systems which uses constant optical path(COP) has been developed. The sum of
the optical path lengths from an object wavefront to an image wavefront remains
constant, and achromatic holographic systems can be easily calculated. Using COP,
a new focusing triplet was designed with wavelength tolerance of 9 nm for
entrance and exit numerical apertures of 0.5. This is 15 times larger than that
for conventional single holographic lens.
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.
SABIC's ULTEM (TM) (polyetherimide) resin has been the choice of material for injection moldable micro lenses and lens arrays in optical communication components such as transceivers due to its unique combination ...
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ISBN:
(纸本)9781628412192
SABIC's ULTEM (TM) (polyetherimide) resin has been the choice of material for injection moldable micro lenses and lens arrays in optical communication components such as transceivers due to its unique combination of physical, thermal and optical properties including high refractive index, low absorption in near IR range, good dimensional stability and high heat performance. It's known that processing conditions affect properties of final parts. Often the processing conditions are optimized for best mechanical properties, while their effect on optical properties is sidelined. In this study, the effect of injection molding processing conditions on optical properties of polyetherimide resin is discussed.
The main difference is a significant expansion of the linear field, which reaches 50 mm in the image plane. However, in this case, a planapochromatic correction must be achieved for the usual visible spectral range. S...
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ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
The main difference is a significant expansion of the linear field, which reaches 50 mm in the image plane. However, in this case, a planapochromatic correction must be achieved for the usual visible spectral range. Such a parameter of objectives, like over large working distances - is an additional advantage.
With the increasing sensor development, smart sensor, advanced sensor, and intelligent sensor, especially, distributed sensors, sensor network and sensor integration are being taken into account for application of our...
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ISBN:
(纸本)0819450464
With the increasing sensor development, smart sensor, advanced sensor, and intelligent sensor, especially, distributed sensors, sensor network and sensor integration are being taken into account for application of our environmental monitoring and Earth source investigation. This paper investigates the development of sensors in Earth observing (EO) satellites, analyzes the current high-resolution EO satellites and presents the direction of new imaging systems in future Earth observing satellite. The purpose of this paper is to contribute to those who are interested in knowing and keeping track of the details of the imaging system of earth observing satellites.
The transfer function theory for large core optical fiber (bare fiber) and fiber cable (LOCAT) reveals a ray's actual interaction with the fiber lightguide. By applying this new tool in a fiber optic instrument de...
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ISBN:
(纸本)081941249X
The transfer function theory for large core optical fiber (bare fiber) and fiber cable (LOCAT) reveals a ray's actual interaction with the fiber lightguide. By applying this new tool in a fiber optic instrument design, we have improved the repeatability and stability of this fiber optic temperature instrument from 4°C to 0.2°C at 1000°C. Several new concepts such as cable bend increments, fiber status, and fiber status stability also are discussed in this paper.
A high-speed, high-precision laser plotter which is called Super Laser Photo Plotter, or S-LPP has been developed. S-LPP has a flat table so that both photographic plates and films can be used, and is capable of writi...
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