We present a very large f/1.O prime focus, all-spherical, all-fused-silica catadioptric camera. It contains a two-element airspaced corrector, an f/0.76 primary mirror, and a singlet final element. It accommodates a chromatic range from 0.3 to 1.1µm or more without refocus. It is optimized with an external entrance pupil but can be reoptimized for other pupil distances. In spite of its 30-in. (76.2-cm) focal length, it delivers 12.6-µm (rms) average image diameters to a 3.6-in.- (9.1-cm-) diameter flat focal surface. It is thus well matched to the (7-15µm) pixels and to the size of a (2 × 2) mosaic of today's largest available CCD's.
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http://dx.doi.org/10.1364/AO.32.006270 | DOI Listing |
Brain Sci
September 2024
Psychology Department, Northeastern University, Boston, MA 02115, USA.
Background: Recent evidence in systems neuroscience suggests that lighting conditions affect the whole chain of brain processing, from retina to high-level cortical networks, for perceptual and cognitive function. Here, visual adaptation levels to three different environmental lighting conditions, (1) darkness, (2) daylight, and (3) prolonged exposure to very bright light akin to sunlight, were simulated in lab to investigate the effects of light adaptation levels on classic cases of subjective contrast, assimilation, and contrast-induced relative depth in achromatic, i.e.
View Article and Find Full Text PDFJ Vis
October 2024
Air Force Research Laboratory, 711th Human Performance Wing, Bioeffects Division, JBSA Fort Sam Houston, TX, USA.
The visual system adapts dynamically to stabilize perception over widely varying illuminations. Such adaptation allows the colors of objects to appear constant despite changes in spectral illumination. Similarly, the wearing of colored filters also alters spectral content, but this alteration can be more extreme than typically encountered in nature, presenting a unique challenge to color constancy mechanisms.
View Article and Find Full Text PDFSci Rep
September 2024
Laboratory for Ultrafast Transient Facility, Chongqing University, Chongqing, 401331, China.
Multiple harmonic generation is a key issue for coherence radiation generated by an electron beam modulated by the seeding laser. A new multiple harmonic generation scheme by combining the angular dispersion-induced microbunching (ADM) with the transverse echo effect, which can be easily generated by using pulsed dipoles, a pulsed quadrupole and a pulsed multipole, is investigated in a multi-bend achromatic storage ring. Simulation results demonstrate a triple of harmonic number compared to the case of pure ADM, making it possible to generate coherent extreme ultraviolet radiation in storage rings.
View Article and Find Full Text PDFPhys Rev Lett
November 2023
State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Hangzhou 310058, China.
The periodic extension of phase difference is commonly applied in device design to obtain phase compensation beyond the system's original phase modulation capabilities. Based on this extension approach, we propose the application of quasiphase delay matching to extend the range of dispersion compensation for meta-atoms with limited height. Our theory expands the limit of frequency bandwidth coverage and relaxes the constraints of aperture, NA, and bandwidth for metalenses.
View Article and Find Full Text PDFWilderness Environ Med
December 2023
School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada.
This Lessons from History article uses science, aviation, medicine, and mountaineering sources to describe some of the effects of hypoxia, illumination, and other environmental conditions on the eye, the central nervous system, and light and color perception. The historical perspective is augmented by an analysis of an informal observation of the altered perception of red color on a deck of playing cards while climbing Mera Peak in the Himalaya. The appearance of a grayer red color on the cards was initially attributed to the effects of hypoxia alone.
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