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2. Condenser (optics) - Wikipedia

   en.wikipedia.org/wiki/Condenser_(optics)

   A condenser (right) and its respective diaphragm (left) A condenser is an optical lens that renders a divergent light beam from a point light source into a parallel or converging beam to illuminate an object to be imaged. Condensers are an essential part of any imaging device, such as microscopes, enlargers, slide projectors, and telescopes.

3. Numerical aperture - Wikipedia

   en.wikipedia.org/wiki/Numerical_aperture

   Due to Snell's law, the numerical aperture remains the same: NA = n 1 sin θ 1 = n 2 sin θ 2. In optics, the numerical aperture (NA) of an optical system is a dimensionless number that characterizes the range of angles over which the system can accept or emit light.

4. Diffraction-limited system - Wikipedia

   en.wikipedia.org/wiki/Diffraction-limited_system

   Memorial in Jena, Germany to Ernst Karl Abbe, who approximated the diffraction limit of a microscope as = ⁡, where d is the resolvable feature size, λ is the wavelength of light, n is the index of refraction of the medium being imaged in, and θ (depicted as α in the inscription) is the half-angle subtended by the optical objective lens (representing the numerical aperture).

5. Oil immersion - Wikipedia

   en.wikipedia.org/wiki/Oil_immersion

   State of the art objectives can have a numerical aperture of up to 0.95. Because sin α 0 is always less than or equal to unity (the number "1"), the numerical aperture can never be greater than unity for an objective lens in air. If the space between the objective lens and the specimen is filled with oil however, the numerical aperture can ...

6. Köhler illumination - Wikipedia

   en.wikipedia.org/wiki/Köhler_illumination

   Köhler illumination is a method of specimen illumination used for transmitted and reflected light (trans- and epi-illuminated) optical microscopy.Köhler illumination acts to generate an even illumination of the sample and ensures that an image of the illumination source (for example a halogen lamp filament) is not visible in the resulting image.

7. Bright-field microscopy - Wikipedia

   en.wikipedia.org/wiki/Bright-field_microscopy

   A bright-field microscope has many important parts including; the condenser, the objective lens, the ocular lens, the diaphragm, and the aperture. Some other pieces of the microscope that are commonly known are the arm, the head, the illuminator, the base, the stage, the adjusters, and the brightness adjuster.

8. Dark-field X-ray microscopy - Wikipedia

   en.wikipedia.org/wiki/Dark-field_X-ray_microscopy

   A monochromatic beam from a synchrotron source illuminates the sample. Objective is the objective lens and Detector is the 2D area detector [1] [7]. In this technique, a synchrotron light source is used to generate an intense and coherent X-ray beam, which is then focused onto the sample using a specialized objective lens.

9. Coherent diffraction imaging - Wikipedia

   en.wikipedia.org/wiki/Coherent_diffraction_imaging

   A field emission electron gun generates a beam with high coherence and high intensity. The beam size is limited to nano area with the condenser aperture in order to ensure scattering from only a section of the nanotube of interest. The diffraction pattern is recorded in the far field using electron imaging plates to a resolution of 0.0025 1/Å.