نتایج جستجو برای: optical instrument
تعداد نتایج: 346252 فیلتر نتایج به سال:
Context. We have observed the Crab Pulsar in the optical with S-Cam, an instrument based on Superconducting Tunneling Junctions (STJs) with μs time resolution. Aims. Our aim was to study the delay between the radio and optical pulse. Methods. The Crab Pulsar was observed three times over a time span of almost 7 years, on two different locations, using three different versions of the instrument,...
PURPOSE Soft contact lenses with spherical base curves have been used for many years. The computation of the refractive powers of these lenses is easy, requiring only that one uses the lens maker equation for thick lenses. Nevertheless, for customized contact lenses, there is yet no reliable method for measuring the higher order optical aberrations. In this study we have developed in the Center...
We describe a compact laser wavelength measuring instrument based on a small diffraction grating and a consumer-grade webcam. With just 1 pW of optical power, the instrument achieves absolute accuracy of 0.7 pm, sufficient to resolve individual hyperfine transitions of the rubidium absorption spectrum. Unlike interferometric wavemeters, the instrument clearly reveals multimode laser operation,...
The alignment of three mirror anastigmatic (TMA) telescopes has been studied since their invention in the 60s. Recently, Thompson et al. reported that other than the conventional uniform coma over the field caused by misalignment, TMA telescopes display only one other misalignment induced aberration, field-asymmetric, field-linear astigmatism. Currently, an instrument with three TMAs is under d...
A method for measuring birefringence by use of thermal-light polarization-sensitive optical coherence tomography is presented. The use of thermal light brings to polarization-sensitive optical coherence tomography a resolution in the micrometer range in three dimensions. The instrument is based on a Linnik interference microscope and makes use of achromatic quarter-wave plates. A mathematical r...
An instrument is demonstrated that can be used for optical detection of honeybees in a cluttered environment. The instrument uses a continuous-wave diode laser with a center wavelength of 808 nm and an output power of 28 mW as the laser transmitter source. Light scattered from moving honeybee wings will produce an intensity-modulated signal at a characteristic wing-beat frequency (170-270 Hz) t...
We describe an optical scattering instrument designed to assess the shapes and sizes of microscopic atmospheric cloud particles, especially the smallest ice crystals that can profoundly affect cloud processes and radiative properties yet cannot be seen clearly using in situ cloud particle imaging probes. The new instrument captures high-resolution spatial light scattering patterns from individu...
We describe an instrument for measuring the magnitude of birefringence of tomographic images and the principal directions of axes that use thermal-light polarization-sensitive optical coherence tomography. The instrument permits full-field measurements with an axial resolution of 1.5 microm and a transverse resolution limited by diffraction. We obtained a sensitivity of 84 dB, limited by shot n...
We describe preliminary results from an optical scattering instrument designed to assess the shapes and sizes of microscopic atmospheric cloud particles, especially the smallest ice crystals, that can profoundly affect cloud processes and radiative properties. The new instrument captures high-resolution spatial light scattering patterns from individual particles down to approximately 1 microm i...
An optical-DSC system was designed, built, tested, calibrated and verified to incorporate into a single device the capability for simultaneous optical cryomicroscopy and differential scanning calorimetry (DSC). This instrument can be used to obtain both visual and thermal data for an individual specimen subjected to a defined freezing and thawing protocol with very little compromise in quality ...
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