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.
In this paper a well-known approach is used for calculation of off-axis three-mirror telescope. It includes usage of conic cross-sections properties, each of the sections forming a stigmatic image. To create a compact...
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ISBN:
(纸本)9781510612082;9781510612075
In this paper a well-known approach is used for calculation of off-axis three-mirror telescope. It includes usage of conic cross-sections properties, each of the sections forming a stigmatic image. To create a compact optical system, a flat mirror aberration corrector is introduced, which is at later stage transformed into a free-form surface in order to compensate field aberrations. Similarly, one can introduce such a corrector in finalized layout for its further optimization and getting a suitable form, including the conversion of multimirrors axial optical system into decentered one. As an example, off-axial Gregory telescope embodiment is used for infrared waveband region, due to the fact that, unlike the Cassegrain telescope, it provides a real exit pupil, and usage of the mirror corrector brings several advantages. Firstly, this feature may be used to include cold stop or adaptive mirror in the exit pupil, wherein corrector is introduced into a converging beam before the focus of the first mirror. Secondly, when placing corrector in the exit pupil of the optical system it is possible to eliminate high and low order aberrations of center point, which in turn improves optical system f-number, and minimize field aberrations. As another example, off-axial Ritchey-Chretien telescope embodiment is used as a good fit for visible region systems. Analysis and calculation results of optical systems with free-form correctors with surfaces, defined by Power polynomial series are presented in this paper. Advantages of different freeform surfaces usage depends on optical system layouts specifics.
An original method to enable the exact solution for the noncemented two-lens objective by means of any number of simultaneous non-linear equations is described. The method is limited to spherical surfaces without dece...
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ISBN:
(纸本)0819432652
An original method to enable the exact solution for the noncemented two-lens objective by means of any number of simultaneous non-linear equations is described. The method is limited to spherical surfaces without decentrations. Separations and refractive indices of glasses are fixed. Ail curvatures of surfaces are indirectly determined in the final stage. The typical meridional aperture aberrations deal with aplanatic and achromatic conditions. Essence of the method relies on formulation functions which contain trigonometric expressions and are nested up to certain depth. The method uses the advanced professional mathematical software which is indispensable for serving the non-linear system of equations. Numerical examples confirm the helpfulness of the method.
This paper describes an application of the diamond turning technology for the manufacturing of cylindrical micro lenses. A lens doublet consisting of an aspherical PMMA lens mounted on a sapphire plate was designed. v...
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ISBN:
(纸本)0819415871
This paper describes an application of the diamond turning technology for the manufacturing of cylindrical micro lenses. A lens doublet consisting of an aspherical PMMA lens mounted on a sapphire plate was designed. various surface curvatures are transferable to a crooked stripe of optical material like polymethylmethacrylat. A diamond tool cuts the circular ring at its outer periphery. The approximately 80 cm long, circular lens stripe relaxes after taking off from the chuck to the original straight condition. Microlenses of any length are gotten by separating the long lens stripe to individual lenses. For a quality inspection the surface was examined by a laser interferometer measurement and the collimation performance of the doublet was tested. The measured surface roughness is better than 12 nm RMS. To apply a 10 mm diode bar a lens with 12 X 1,5 mm2 entry aperture was used in the collimating tests. Experimental results show collimating rates for high performance diode laser applications of 70% in a divergence angle of about 4 mrad.
Ball Aerospace is building the Cryogenic Telescope Assembly (CTA) for the Space InfraRed Telescope Facility (SIRTF) project and stray light control is a critical part of this effort. The heliocentric orbit where the S...
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ISBN:
(纸本)0819432652
Ball Aerospace is building the Cryogenic Telescope Assembly (CTA) for the Space InfraRed Telescope Facility (SIRTF) project and stray light control is a critical part of this effort. The heliocentric orbit where the Sun is never allowed to illuminate the CTA and the Earth is relatively far away is a key feature for stray light control. Mirror and paint BRDFs were measured at various SIRTF wavelengths in order to provide inputs for the stray light models. Stray light from telescope self emission, a distant point source, and the galaxy were analyzed. The design ensures that stray light will be less than 21% of the celestial background at all SIRTF wavelengths.
In this paper, combining refractive and diffractive effects, a new kind of infrared lenses with wavelength 10.6 mu m was designed and produced for CO2 laser material processing. This refractive-diffractive lens (RDL) ...
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ISBN:
(纸本)0819422517
In this paper, combining refractive and diffractive effects, a new kind of infrared lenses with wavelength 10.6 mu m was designed and produced for CO2 laser material processing. This refractive-diffractive lens (RDL) converts a CO2 laser beam into the rectangular shape with light intensity distribution in the concave shape at x-direction. A method which employs input aperture division and geometrical transformation technique for obtaining a better initial phase distribution of the iteration is presented. The experimental results show that the desired shape of the output light beam was obtained with a high efficiency in energy utilization.
A new type of Galilean binoculars is presented. The objective lenses are composed of a cemented doublet and a positive meniscus, and the eyepiece is a negative thick meniscus. In addition, all of the surfaces except t...
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ISBN:
(纸本)0819406554
A new type of Galilean binoculars is presented. The objective lenses are composed of a cemented doublet and a positive meniscus, and the eyepiece is a negative thick meniscus. In addition, all of the surfaces except the gluing surface are concave toward the eye-side of the system. So the structure is suitable for both increasing the field of view and decreasing the dimensions. It increases the vision angle by 46.5% and reduced the dimensions approx 2.33 times. The characteristics are: the magnifying power, 2.3; the object vision angle, 32 deg when its interpupillary distance is 6 mm, 27,36 deg when its interpupillary distance is 8 mm; the total of the telescope 29 mm; and the full objective aperture, (Phi) 35 mm.
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.
In missile applications, new counter measure methods are getting more complex. To discriminate and detect counter measure and to understand target signature from scene is getting harder. Because of all that concerns, ...
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ISBN:
(数字)9781510637719
ISBN:
(纸本)9781510637719
In missile applications, new counter measure methods are getting more complex. To discriminate and detect counter measure and to understand target signature from scene is getting harder. Because of all that concerns, using triple-mode seeker for a system solution is a good solution for system total performance. By this way, tri-different wavelength could be used for same system and same scene. In this study, triple mode system's opticaldesigns have been made for mid-wave infra-red imaging, long-wave infra-red imaging and short-wave infrared imaging. opticaldesigns performances have been illustrated in simulation results. Finally, conceptual design of triple mode seeker will be summarized.
We describe the features of the optical system for Terrestrial Planet Finder, a space-based, cryogenic (35 K) interferometer for direct detection of Earth-type planets around nearby stars. Destructive interference in ...
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ISBN:
(纸本)0819432652
We describe the features of the optical system for Terrestrial Planet Finder, a space-based, cryogenic (35 K) interferometer for direct detection of Earth-type planets around nearby stars. Destructive interference in a stellar interferometer suppresses stellar glare by a factor of several thousand or more, and phase chopping distinguishes planet light from symmetric backgrounds. The mid-infrared (7-20 mu m) is favorable for detecting planetary emission relative to that from the star, and this spectral region also offers important molecular signatures indicative of key atmospheric gases.
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