A spaceborne telescope has been designed and analyzed for a 2-micron solid state coherent lidar system operating on a satellite. The optical system consists of a large off-axis reflective telescope, a large-aperture d...
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ISBN:
(纸本)0819418994
A spaceborne telescope has been designed and analyzed for a 2-micron solid state coherent lidar system operating on a satellite. The optical system consists of a large off-axis reflective telescope, a large-aperture diffractive scanner, an image derotator and a lag angle compensator. Due to the orbiting motion of the satellite and scanning, the boresight of the telescope shifts during the round trip travel time of the laser pulses to the target. In a coherent lidar system utilizing optical heterodyne detection, the relative alignment of the received signal with respect to the local oscillator beam is particularly critical. Two compensators have been designed to correct the boresight errors as well as the wavefront errors caused by beam wandering due to the boresight changes. Several design approaches for the compensators have been investigated. The optical and optomechanical design issues for such a system are discussed. The results of optical performance, modeling, and tolerance analysis for the telescope are also presented.
Although considered as low level processing, edge detection is a crucial step in object and image recognition. Such an operation can be implemented in real time by use of an appropriate transmittance in the Fourier pl...
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ISBN:
(纸本)0819418994
Although considered as low level processing, edge detection is a crucial step in object and image recognition. Such an operation can be implemented in real time by use of an appropriate transmittance in the Fourier plane of a so-called VanderLugt optical correlator. The performance of this scheme depends on both the contour enhancement operator chosen and the spatial filter design. For the latter point, great flexibility can be obtained by using computer generated holography techniques. In this framework, we propose to implement a particular contour extraction primitive, namely the summation of the partial derivatives of an input function, using a direct binary search (DBS) procedure for the design of the spatial filter. This first approach leads, however, to a non-detection of the contours oriented at 45 degrees to the abcissa axis. To solve this problem we propose a modified gradient holographic filter. A theoretical analysis and simulation results are presented.
We have developed a low transmission loss prism for optical switches suitable for optical fiber systems which monitor and control factory equipment. We have realized the low transmission loss prism by using the geomet...
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ISBN:
(纸本)0819418994
We have developed a low transmission loss prism for optical switches suitable for optical fiber systems which monitor and control factory equipment. We have realized the low transmission loss prism by using the geometrical property of ellipsoids and a newly developed optical power evaluation computer program which facilitates estimating the coupling efficiency between two optical fibers considering total reflection phenomena, numerical aperture and far field pattern of the optical fiber for an aspherical optical system. The transmission loss of the present ellipsoidal prism is 5 dB for the plastic fiber with the core diameter of 1 mm, and 5.8 dB for polymer clad fiber with core diameter of 0.2 mm. The present ellipsoidal prism improves transmission loss by 4 dB as compared with the conventional spherical prism for the optical fibers usually adopted to the optical fiber systems. The calculated loss and experimental loss agreed well. This agreement confirms the usefulness of our computer program.
currentopticaldesign software provides little support for the mundane human oriented tasks of personal project management. Project management tools from other domains are not readily applied to the opticaldesign pr...
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ISBN:
(纸本)0819418994
currentopticaldesign software provides little support for the mundane human oriented tasks of personal project management. Project management tools from other domains are not readily applied to the opticaldesign process. This paper discusses the salient issues and describes (via case studies) possible solutions to this problem.
Combination of global optimization technique with 3-D order monochromatic and first order chromatic aberrations theory may be useful to search an initial system for opticaldesign. Multivariant synthesis of an optical...
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ISBN:
(纸本)0819418994
Combination of global optimization technique with 3-D order monochromatic and first order chromatic aberrations theory may be useful to search an initial system for opticaldesign. Multivariant synthesis of an optical system consisting of thin components is discussed on the basis of Slusarev's theory of principal parameters.
Hybrid optics - diffractive structures on a refractive substrate - have some specific applications in the lower of the two thermal infrared wavebands. These applications include optical systems where simplicity and/or...
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ISBN:
(纸本)0819418994
Hybrid optics - diffractive structures on a refractive substrate - have some specific applications in the lower of the two thermal infrared wavebands. These applications include optical systems where simplicity and/or low mass are major requisites. In many cases, however, the use of diffractive surfaces is limited to those substrate materials that can be diamond-machined successfully. The paper examines the optical merits of several substrate materials and gives design examples where hybrid optics have major advantages relative to conventional optics in terms of mass, thermal defocus, and complexity.
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...
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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.
A description of the newly deployed ADONIS, daylight speckle-imaging camera, including opticaldesign and layout, electronics, data acquisition system, and processing systems is given. Considerations of operating this...
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ISBN:
(纸本)0819418994
A description of the newly deployed ADONIS, daylight speckle-imaging camera, including opticaldesign and layout, electronics, data acquisition system, and processing systems is given. Considerations of operating this system on a large telescope under daylight conditions are discussed, along with alignment to the telescope and system testing. Sample pre- and post-processed images are included.
The generalized Coddington equations from caustic theory, the Abbe sine condition, and the constant optical path length condition have been used to design two-mirror microscope systems. These two-microscope systems ar...
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ISBN:
(纸本)0819418994
The generalized Coddington equations from caustic theory, the Abbe sine condition, and the constant optical path length condition have been used to design two-mirror microscope systems. These two-microscope systems are free of two of the three aberrations - spherical aberration, coma, or astigmatism, depending on which two of the three design conditions are used. The optical performance of the resulting two-microscope systems has been compared to that of the Schwarzschild microscope and the Head microscope. The goal of this study is to identify design methods for reflective systems which will yield diffraction limited performance for large numerical apertures and fields of view. Also, these design methods are being extended to a three-mirror telescope.
Abnormal dispersive liquids have proven quite useful in the design of apochromatic optical systems for the visible and ultraviolet spectral regions. Furthermore, liquids with extended ultraviolet transmission can be v...
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ISBN:
(纸本)0819418994
Abnormal dispersive liquids have proven quite useful in the design of apochromatic optical systems for the visible and ultraviolet spectral regions. Furthermore, liquids with extended ultraviolet transmission can be very useful in the design of optical systems for use in the ultraviolet, whether or not they are abnormally dispersive. The results of investigations into optical properties of several liquids transparent in the ultraviolet are presented. Intense UV irradiation of the liquids was found to produce changes in both the UV transmission and refractive index. Methods of preventing these changes through the addition of a special chemical were investigated. 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.
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