نتایج جستجو برای: external reflectors
تعداد نتایج: 192609 فیلتر نتایج به سال:
The results of ultrasonic tests are usually displayed as A-scan signals. In an A-scan signal, reflections of ultrasonic wave form different reflectors are shown as sharp echoes on a time by amplitude display. Interpretation of these echoes can sometimes be quite difficult and usually requires knowledgeable and experienced specialists. There exist other methods of displaying the ultrasonic test...
Body parts that can reflect highly polarized light have been found in several species of stomatopod crustaceans (mantis shrimps). These polarized light reflectors can be grossly divided into two major types. The first type, usually red or pink in color to the human visual system, is located within an animal’s cuticle. Reflectors of the second type, showing iridescent blue, are located beneath t...
Millimeter-wave (MMW) radars have become standard cloud research tools because of their high sensitivity to small cloud particles, low prime power requirements, and compact size. However, MMW radars are more likely to suffer gain variations, so their calibration becomes crucial. Radar systems can be calibrated absolutely by various methods such as measurements of individual system parameters, c...
We demonstrate the mode locking of external-cavity semiconductor lasers by using a saturable Bragg reflector as an external reflector. Output pulses of 1.9 ps were generated from the semiconductor lasers without dispersion compensation. By coupling the output to a standard single-mode filter with a length of 35 m to compensate for the linear chirp, we have achieved mode-locked pulse durations a...
Consider the problem of placing reflectors in a 2-D environment in such a way that a robot equipped with a basic laser can always determine its current location. The robot is allowed to swivel at its current location, using the laser to detect at what angles some reflectors are visible, but no distance information is obtained. A polygonal map of the environment and reflectors is available to th...
The use of the generalized Snell's law opens wide possibilities for the manipulation of transmitted and reflected wavefronts. However, known structures designed to shape reflection wavefronts suffer from significant parasitic reflections in undesired directions. We explore the limitations of the existing solutions for the design of passive planar reflectors and demonstrate that strongly nonloca...
The spectral properties of high-reflection mirrors imbued with two-dimensional (2D) subwavelength periodicity are investigated. The reflectors are designed in a silicon-on-glass film that is partially etched to implement a zero-contrast interface between the grating pillars and the sublayer, thereby annulling the local reflections and phase changes associated with hard interfaces. This approach...
Investigated are IR light-emitting diodes with 850 nm radiation wavelength, based on AlGaAs/GaAs heterostructures grown by the method of MOC-hydride epitaxy a Bragg reflector and additional “reflecting” layer Al0.9Ga0.1As, which ensures decrease optical losses generated radiation. Developed is post growth technology for forming frontal ohmic contacts texturing surface, increase extraction effic...
A design methodology for collapsible rib-tensioned surface (CRTS) reflectors is presented. Offset configurations are explicitly addressed. For a reflector with aperture of 10 m diameter and focal length of 7.8 m, a root-mean-square surface accuracy of about 2 mm is achievable; this result scales linearly with the diameter. The design of a 1.5 m diameter prototype is presented, and the accuracy ...
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