Aperture stop

Tdrdk P, Sheppard C J R and LaczikZ 1996 Dark field and differential phase contrast imaging modes in confocal microscopy using a half aperture stop Optik 103 101-6... 

Deformable mirrors are usually placed at a greatly reduced image of the telescope entrance pupil - the typical diameter of PZT or PMN based deformable mirrors is in the range 10-20 cm. A completely different approach is to make one of the telescope mirrors deformable, and the best choice is the secondary mirror (relatively small and usually coincides with the aperture stop for in-... 

Etendue is a characteristic of an optical instrument. It is a measure of the light gathering power, i.e. the power transmitted per radiance of the source. A is the area of the source (or image stop) Q is the solid angle accepted from each point of the source by the aperture stop. 

As a rule of thumb, no parts of the housing, lens holders, or the inside of optical tubes should be visible from the active area of the detector. This can be achieved by circular stops that restrict either the field of view of the detector (field stops) or the effective aperture of a beam (aperture stops). The term baffle is often used baffles are cylindrical or conical tubes or circular stops that keep off unwanted light from the detector [71]. 

Another way to suppress stray light is through field stops and aperture stops. A field stop is placed in a conjugate image plane of the excited spot in the sample. An aperture stop is placed most efficiently in the image plane of another aperture, which can be another stop, a lens, or a mirror. Two examples are shown in Fig. 7.29. A lens, LI, focuses a laser beam into a sample. The light emitted by the... 

Fig. 1. TIRF microscope. (A) A view of the TIRF system. (B)View looking down on the back of the microscope (environmental chamber at bottom, back of the system at the top). Arrow b indicates the location of the Selection Prism containing the 80%/ 20% beamsplitter. Pulling the knob at the top to its full upwards position sets the beamsplitter to 100%/ 0% (all Epi-illumination input to the microscope). Pushing it downward sets the beamsplitter to 80% laser and 20% epifluo-rescence illumination. (B ) Location of the Field Diaphragm and the Field Stop on the epifluorescence arm of the split box. Two arrows AS and FS indicate Aperture Stop and Field Stop, respectively. Adjustment of these is vital for good IRM imaging. (B ) The laser input from which the screw white arroW) for TIRF angle adjustment projects. This pair of screws laterally translocates the laser path off center in the objective so that the angle of reflection is altered.

Adjust the size of the Aperture Stop (AS, a light intensity control after the Hg bulb and right before Selection Prism in the light path) so that light extends to just beyond the size of the preview window (Fig. lb and see B , AS). 

Radiation from the other leg of the interferometer was focused onto a 2S-pm diameter pinhole which acted as an aperture stop at the face of a standard Dumont 6911 type S-1 photomultiplier. This provided a relatively accurate method for superimposing the two beams [7.24], This is critical since the double-quantum response is inversely proportional to the illuminated area A. The beams were adjusted to achieve maximum output from the 6911 photomultiplier tube, a procedure which was often difficult and required a great deal of care. 

Aperture stop An opening, usually circular, that limits the total radiant power entering a lens system. The iris is the aperture stop of the eye. 

Pupil 1 An image of the aperture stop of an optical system. 2 The black circular opening in the center of the iris (of the eye), which permits light to pass to the retina. 

The basic camera, like the eye, consists of a lens and a photosensitive surface. Also like the eye, the camera controls the intensity of the light falling onto the photosensitive surface by adjustments of the diameter of the aperture stop, usually an iris diaphragm in a professional camera. Unlike the eye, the camera captures only instantaneous images, and the camera varies the duration of the exposure to light, or the exposure time, depending on the intensity of the light and the sensitivity of the photosensitive surface. Also unlike the eye, the camera usually has a flat photosensitive... 

FIGURE 17 A microscope illuminator using Kohler illumination. The aperture stop is located at the primary focal point of the condensing lens. 

Tracing two bundles of rays through the telescope reveals a waist just behind the secondary focal point of the eyepiece. The waist is the image of the aperture stop, that is, of the ring that holds the objective in place. It is called... 

An aperture stop is used to eliminate light from an unwanted direction. In special cases various types of spatial filters are inserted in order to cut out unwanted modes. 

Receiver solid angle (Q) the solid angle subtended by the receiver aperture stop from the sample origin ... 

In many cases the field stop is set by the detector size however, as the aperture stop approaches the field stop the risk of seeing unwanted stray light increases. Other receiver geometries may be used. They all have effective aperture and field stops and it is good operating practice to make them well defined (Fig. A3). 

C. Y. Chang, S. Y. Yang, M. S. Wu, L. T. Jiang, and L. A. Wang, "A novel method for fabrication of plastic microlens array with aperture stop>s for projection photolithography," Japanese Journal of Applied Physics Part 1-Regular Papers Brief Communications Review Papers, vol. 46, pp. 2932-2935, May 2007. 

Fig. 9 Directed flares forming a six pointed star due to scattering at the aperture stop (image shows also some veiling glare)...

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