Objective lenses lens type

Dark-field illumination is classified into three types. The first one is for a microscope equipped with low numerical aperture (NA) objective lenses (see Fig. 1). To cast a shadow at the objective lens, a ring-slit as shown in Fig. IB is inserted into the light path. The second is for highNA (>0.5) objective lenses. Special, ready-made dark-field condensers or lenses are used for dark-field illumination. The third is independent... 

F results in a magnified image produced at a considerable distance from F on the other side of the the lens, which is convenient for viewing. In a compound microscope, the most common type, an additional lens, the eyepiece, is added to magnify the image produced by the objective lens. 

Thermal lens microscopy (TLM) is a type of photothermal spectroscopy. TLM depends on the coaxial focusing of the excitation and probe laser beams (see Figure 7.20). Which is achieved using the chromatic aberration of a microscopic objective lens [731]. The excitation beam can be provided by a YAG laser (532 nm) [846,1021] or an Ar ion laser (514.5 nm [846] or 488 nm [732]).The probe beam can be provided by a He-Ne laser (632.8 nm) [846,1021], After optical excitation of the analyte molecules, radiationless relaxation of the analytes occurs,... 

A 6-inch, f/3.8 objective lens with coated optics was used in conjunction with a 4V2-inch extension tube. Three No. 5 medium peak flash bulbs connected in series provided the proper background lighting. The Dynafax capping shutter is equipped with a synchromatic delay which provided synchronization for this type of lamp. 

The most precise type of refractometer is the immersion refractometer. It contains a prism fixed at the end of an optical tube containing an objective lens, an engraved scale reticule, and an eyepiece. It also contains an Amici compensating prism (see below). In use, the instrument is dipped into a beaker of the liquid clamped in a water bath for temperature control. A mirror in the bath or below it reflects light into the bottom of... 

The electron microscope can be operated to form on the fluorescent screen either (i) a diffraction pattern of the specimen or (ii) one of several types of image, depending on which beams are allowed to pass through the aperture in the back focal plane of the objective lens. The geometry of the electron diffraction pattern will be discussed in detail in Chapter 3. 

Figure 16.19 shows the spatial-frequency distributions of bit data recorded with focused laser beam and coherent optical transfer function (CTF) of reflection type confocal microscopeFigure 16.19a shows a spatial-frequency distribution of bit datum recorded in very thick medium. This distribution coincides with the spatial-frequency distribution of the focused light to record the bit datum, because the bit is recorded with the focused beam. It is assumed that the NA of the objective lens is given by n sin a and k =l ulk, where A denotes the wavelength. 

Two-photon three-dimensional (3D) micro- and nanofabrication using a femtosecond laser have been used to create various types of 3D micro- and submicrometer structures [70, 74, 260, 265, 574], A microscope with axial (z) and lateral (r) resolutions given by Eqs. (77) and (78) was used for laser microfabrication [574]. Wavelength of irradiation light (/.), refractive index of the material (/ ), and numerical aperture of the objective lens (NA) influence the resolution in axial and lateral directions. 

In microelectrophoresis the measurement is carried out by filling the cell with the suspension and applying a known potential. With an objective lens that gives a small depth of focus, the microscope is focused at the stationary level and the time for a particle to move a known distance is measured. This technique is also applicable with several different types of particles present. 

Figure lb, c illustrates the optical configuration of objective-type TIRFM on an inverted microscope see Note 1). An objective lens with high numerical aperture (>1.4) is mounted on the inverted microscope (rrrNote 2). Alaser beam is passed through a neutral density filter and a beam expander to adjust its power and diameter. In order to convert the polarization of the beam from linear to circular, we used a quarter-wave plate. The incident laser beam is focused on the back focal plane (BFP) of the objective (rrrNote 3). To perform singlemolecule imaging, a laser beam is incident to the specimen at a power of 1 mW on a circular area 30 pm in diameter. 

The objective-type TIRFM is based on the fact that a laser beam off-axis at the BFP of the objective leaves the objective lens with an angle. When the incident beam is focused at the center of the objective on-axis, the microscope can be used as a standard EPI-fluorescence microscope. When the path is shifted from the center to the edge off-axis (i.e., between... 

As explained previously, most SEMs employ a "pinhole" objective lens and single SE detector. In this arrangement, there is no discrimination between the various types of SEs detected, and all contribute towards image formation. 

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