Topic
Parabolic reflector
About: Parabolic reflector is a research topic. Over the lifetime, 3375 publications have been published within this topic receiving 30735 citations. The topic is also known as: paraboloid reflector & paraboloidal reflector.
Papers published on a yearly basis
Papers
More filters
TL;DR: By selective deposition of evaporated dielectrics it was found possible to form aspherical surfaces on plane glass plates which, when used with a lens, made the combination free from spherical aberration.
Abstract: By selective deposition of evaporated dielectrics it was found possible to form aspherical surfaces on plane glass plates which, when used with a lens, made the combination free from spherical aberration. A theory is given for the calculation of the correcting surfaces, and the experimental procedure for their preparation is described. The results are shown by means of ronchigrams.
17 citations
TL;DR: In this article, the authors designed a thermal imaging system for studying shock temperatures produced inside a gas gun at Sandia National Laboratories, which can collect low f/# light over a broad spectral range, for high-speed imaging.
Abstract: Thermal imaging is an important, though challenging, diagnostic for shockwave experiments. Shock-compressed materials undergo transient temperature changes that cannot be recorded with standard (greater than ms response time) infrared detectors. A further complication arises when optical elements near the experiment are destroyed. We have designed a thermal-imaging system for studying shock temperatures produced inside a gas gun at Sandia National Laboratories. Inexpensive, diamond-turned, parabolic mirrors relay an image of the shocked target to the exterior of the gas gun chamber through a sapphire vacuum port. The 3000-5000-nm portion of this image is directed to an infrared camera which acquires a snapshot of the target with a minimum exposure time of 150 ns. A special mask is inserted at the last intermediate image plane, to provide dynamic thermal background recording during the event. Other wavelength bands of this image are split into high-speed detectors operating at 900-1700 nm and at 1700-3000 nm, for time-resolved pyrometry measurements. This system incorporates 90-degree, off-axis parabolic mirrors, which can collect low f/# light over a broad spectral range, for high-speed imaging. Matched mirror pairs must be used so that aberrations cancel. To eliminate image plane tilt, proper tip-to-tip orientation of the parabolic mirrors is required. If one parabolic mirror is rotated 180 degrees about the optical axis connecting the pair of parabolic mirrors, the resulting image is tilted by 60 degrees. Different focal-length mirrors cannot be used to magnify the image without substantially sacrificing image quality. This paper analyzes performance and aberrations of this imaging diagnostic.
17 citations
TL;DR: In this article, a rigorous three-dimensional ray tracing program was developed to evaluate the reflection losses and their effect on the concentration of a two-stage compound parabolic concentrator with two configurations: a parabolic dish as a first stage and a Cassegrainian as a second stage.
17 citations
Patent•
30 Mar 2009TL;DR: In this paper, a vehicle lamp using the LED lighting unit can have a favorable light distribution that can be perceived as a single, integrated lighting surface and which can be used for a headlight, a tail lamp, etc.
Abstract: An LED lighting unit, and a vehicle lamp using the LED lighting unit can have a favorable light distribution that can be perceived as a single, integrated lighting surface. The LED lighting unit can include a plurality of base boards, a plurality of LED light sources located on each mounting surface of the base boards, a plurality of parabolic reflectors and at least one V-shaped reflector configured to locate between the adjacent parabolic reflectors. Because each of the LED light sources is located substantially at each focus of the parabolic reflectors and the at least one V-shaped reflector, light emitted from the LED light sources can be illuminated as a single, integrated light via their reflectors. Thus, a vehicle lamp using the LED lighting unit can have a favorable light distribution that can be perceived as a single, integrated lighting surface and which can be used for a headlight, a tail lamp, etc.
16 citations
TL;DR: This work uses the Richards-Wolf vector field equation to investigate the electric energy density distribution of a beam focused with a parabolic mirror and confirms that the focal spot of a strongly focused beam is affected by severe coma, even for very small tilting of the mirror.
Abstract: A parabolic mirror illuminated with an incident collimated beam whose axis of propagation does not exactly coincide with the axis of revolution of the mirror shows distortion and strong coma. To understand the behavior of such a focused beam, a detailed description of the electric field in the focal region of a parabolic mirror illuminated with a beam having a nonzero angle of incidence is required. We use the Richards–Wolf vector field equation to investigate the electric energy density distribution of a beam focused with a parabolic mirror. The explicit aberration function of this focused field is provided along with numerically calculated electric energy densities in the focal region for different angles of incidence. The location of the peak intensity, the Strehl ratio and the full-width at half-maximum as a function of the angle of incidence are given and discussed. The results confirm that the focal spot of a strongly focused beam is affected by severe coma, even for very small tilting of the mirror. This analysis provides a clearer understanding of the effect of the angle of incidence on the focusing properties of a parabolic mirror as such a focusing device is of growing interest in microscopy.
16 citations