Typical optical arrangement

Figure C 1.4.8. (a) An energy level diagram showing the shift of Zeeman levels as the atom moves away from the z = 0 axis. The atom encounters a restoring force in either direction from counteriDropagating light beams, (b) A typical optical arrangement for implementation of a magneto-optical trap.

Figure 7.10 Typical optical arrangements employed for detection of (a) vapour phase (b) liquid phase and (c) solid chromatographic phases. After White [167], Reprinted from R. White (ed.), Chromatography/Fourier Transform Infrared Spectroscopy and Its Applications Marcel Dekker Inc., New York, NY (1990), by courtesy of Marcel Dekker Inc.

A third and important requirement for lasing action is to have sufficient optical gain irrespective of the active medium. The optical gain is achieved by multiple passes of the photons through the population-inverted medium. Multiple passes of photons is achieved by placing the active medium in an optical resonator. The optical resonator consists of two or more mirrors. A typical optical arrangement for a laser system is shown in Fig. 12.13. 

Fig. 12.13. Typical optical arrangement for a laser air-borne depth sounder (LADS).

The essential elements of a CARS setup, the details of the component requirements, and potential concerns about CARS measurements are discussed in this section. A typical optical arrangement for the CARS system is shown in Figure 13.8. The heart of the CARS system is the neodymium-yttrium aluminum garnet (Nd-YAG)... 

FIGURE 6.8 Typical side-on (top) and front-face (bottom) optical arrangements for laser flash photolysis to detect transient changes in the absorption spectrum. Abbreviations S = light source (probe) L = lens C = cell holder + cell (typical path lengths 1-0.5 cm (top) and 0.5-0.2cm (bottom)) M = mirror Mo — monochromator P = photomultiplier. The most commonly used lasers deliver powers equal to or larger than 0.5 MW per pulse. 

Figure 3.24 illustrates a typical optical layout for a visible and near-ultraviolet doublebeam recording spectrophotometer. The arrangement is very similar to that in Figure 3.23... 

These are highly selective and among the most sensitive of detectors. They are based on filter fluorimeters or spectrofluorimeters (p. 376) but are usually purpose-designed for hplc or capillary electrophoresis (p. 168). The optical arrangement of a typical detector using filters is shown in figure 4.30. Excitation and emission wavelengths are selected by narrow bandpass filters. 

Pig. 4.25. Schematic pathway of radiation in a typical thin-layer chromatography scanner. This set-up allows the measurement in transmission, reflection and fluorescence. The optical arrangement and the light source are varied acccnding to the problem. 

In order to determine the positions of these darkened images or spectral lines, the plate or film is positioned in a comparator or microphotometer which projects a portion of the spectrum onto a viewing screen for direct comparison with a known or standard spectrum. The optical arrangement and photograph of a commercial microphotometer is shown in Figure 11.3. Typically, an iron spectrum will also be... 

A typical experimental arrangement for measuring RF transitions between Zee-man levels in the upper state of the optical transition is shown in Fig. 5.8. A coil around the sample cell provides the RF field, while the dc magnetic field is produced by a pair of Helmholtz coils. The fluorescence induced by a polarized dye laser beam is monitored by a photomultiplier through a polarizer as a function of the radio frequency co f [514]. 

A typical experimental arrangement is depicted in Fig. 6.30 [686]. The optical pulse from the mode-locked laser is spatially and spectrally broadened in the optical fiber and then compressed by the grating pair. The dispersion of the grating pair can be doubled if the pulse is reflected by the mirror M and passes the grating pair again. Pulse widths of 16 fs have been obtained with such a system [688]. 

A typical experimental arrangement for level-crossing spectroscopy is depicted in Fig. 12. Atoms or molecules in a homogeneous magnetic field B = 0,0, B are excited by the polarized optical wave E = Ey cos(cot — kx) and tuned to the transi-... 

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