Cylindrical lens

Curved crystals can be used in three different ways, as we shall see. Each crystal is a cylinder that will be examinedjn right-section. Each receives x-rays from a slit parallel to the lens axis, the slit appearing as a point in the drawings. Such a slit is necessary with a cylindrical lens if the sample has breadth as well as length. 

Figure 5 shows the dependence of the total emission intensity on the excitation intensity and its spectral width obtained from DCM-encapsulated dendrimers. A nitrogen laser (wavelength of 337 run, pulse duration of 4 ns, and repetition rate of 10 Hz) was used as the excitation source. A cylindrical lens focused the excitation beam onto a stripe 200 pm wide on a quartz cuvette... 

Fig. 2.14 The scheme of the cylindrical lens method for diffusion coefficient measurement (1) the source with the horizontal slit (2) the condenser supplying a handle of parallel beams (3) the cuvette with a refraction index gradient where the beams are deflected (4) the objective lens focusing the parallel beams to a single point (5) the optical member with an oblique slit and a cylindrical lens (6) the photosensitive material...

Fig. 5.10. The top two panels show the transverse image of two filaments (top left panel) and the corresponding interference pattern (top right panel) observed in the far field obtained using a cylindrical lens. The lower panels show the corresponding images when a spherical lens is used...

Figure 6.5. Diode laser head. The laser diode output passes successively through a three-element collimating lens, cylindrical lens, and anamorphic prism pair to become a fully collimated, circular, anastigmatic beam. Redrawn from Melles Griot product literature.

The use of a linear detector array in the image plane of a polychromator in place of the fluorescence monochromator in Figure 12.1 enables the parallel data accumulation of complete fluorescence spectra. Silicon photodiode arrays, operated in a CCD mode(34) are the most widely used detector elements. The spectral response of the diodes enables fluorescence to be detected from the near-UV up to ca. 1100 nm with a peak response in the near-IR. Up to 8192 elements are now available commercially in a single linear array at low cost. However, the small length of each element (ca. 10 [im) presently limits sensitivity and hence cylindrical lens demagnification is often necessary. 

Figure 2. Transient Raman spectra of Ni(PP) (60-80 ]iM) in pyrrolidine. Traces a) and b) were obtained with 406 nm excitation at high and low power, respectively, while traces c) and d) were generated with 420 nm excitation (which i.s a compromise frequency which resonantly enhances both species to some extent) at high and low power, respectively. For low power spectra the average laser power (at 10 Hz) was. 75-1.0 mW. The beam was only slightly focused onto the sample with a cylindrical lens. High power spectra were generated with 5-6 mW of average laser power sharply focused at the sample via a spherical lens. Spectra are the unsmoothed sum of 3-5 scans at 7-9 cm" spectral resolution.

ISI sector electrostatic energy spectrometer Einzel cylindrical lens Quadrupole... 

This may be inserted into the V(z) formula for a cylindrical lens to give... 

Figure 6. Instrumental schematic for vacuum UV photofragmentation-laser induced fluorescence measurement of ammonia SHGC, second harmonic generation crystal SFMC, sum frequency mixing crystal BS, beam splitter BD, beam dump TP, turning prism CL, cylindrical lens R, reflector TD, trigger diode OSC, oscillator cell AMP, amplifier cell BE, beam expander G, grating OC, output coupler M, mirror BC, beam combiner L, lens A, aperture PD, photodiode SC, sample cell RC, reference cell FP, filter pack SAM.PMT, sample cell photomultiplier REF.PMT, reference cell photomultiplier PP, additional photomultiplier port EX, exhaust and CGI, calibration gas inlet to flow line. (Reproduced with permission from reference 15. Copyright 1990 Optical Society of America.)...

To alleviate this stringency, the beam-focusing lenses most frequently used in today s cytometers are a compromise cylindrical lens combinations provide an elliptical spot, for example, 10-20 by 60 pm in size, with the short dimension parallel to the direction of cell flow and the longer dimension perpendicular to the flow (Fig. 3.1). By retaining a wide beam diameter across the direction of flow, an elliptical illumination spot can provide considerable side-to-side tolerance,... 

In experiments with liquid solutions laser beam was focused inside the parallelepiped or cylindrical quvettes. The beam had the minimal cross section diameter not lower then 0.2 mm. In experiments with solid samples the beam was stretched in one direction by means of cylindrical lens, so the ellipse projected on a surface had dimensions of about 2x0.2 mm2. In such conditions the density of exciting light power did not excite 65 W/cm2 for the experiments with liquids and was at least 10 times smaller for the... 

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