Focusing optics

The experiment was carried out by a continuously working Nd YAG-laser fabricated by NEC. The laser has a maximum output of 1200 W and is controlled by handling facility with a linear axle. A stage index fiber optical waveguide with a diameter of d=1000 pm was used for the control of the beam. The focusing optics consist of a focusing lens (f=l 16 mm) and a collimation lens (f=70 mm). 

Figure 2 presents a schematic view of the ion source region in the PAI configuration. A second high-irradiance, frequency quadrupled pulsed Nd—YAG laser is focused parallel to and above the sample surface, where it intercepts the plume of neutral species that are produced by the ablating laser. Appropriate focusing optics and pulse time-delay circuitry are used in this configuration. 

Fig. 1. Schematic of PAF-V. Key DM, drive motor SA, screw assembly RSA, reactant solution A RSB, reactant solution B DS, drive syringes SV, main switching valves PD, photodetector WB, water bath WA, waste FO, focusing optics M, monochrometer RS, receiving syringe DL, deuterium lamp TL, tungsten lamp ACS, adjustable cell support C, mixing/observation cell W, quartz windows A, reactant A entrance to cell B, reactant B entrance to cell E, product exit from cell RCS, rigid cell support T, a portion of the 4.6 m of coiled tubing not shown for clarity. Reproduced from Ref. (1) by permission of the Royal Society of Chemistry.

Photodiodes occur in many different varieties and are useful in both steady-state and time-resolved fluorescence studies. Photodiodes designed for use in steady-state or on microsecond time-scales are inexpensive and have effective areas up to a few square millimeters, and are capable of efficiently matching to simple focusing optics. However, as the temporal resolution increases so does the cost, and the effective area has to be reduced. For example, APDs with response times in the 50 psec region have effective diameters ofca. 10 /small active area of high-speed devices is currently the primary drawback in fluorescence studies. Also, photodiodes other... 

FIGURE 7.6 Schematic of a laser-induced fluorescence detector. A lamp with focusing optics and an appropriate band-pass filter could be used in place of the laser excitation when tightly collimated light is not required. The emitted fluorescence is detected by a PMT that can be operated in current mode or photon counting mode. Inset shows the mutually perpendicular arrangement of excitation, capillary, and detection optics. 

Atomic emission from the plasma is focused on to the entrance slit of the monochromator using a combination of convex or plano-convex lenses or a concave mirror. The combination of focusing optics, monochromator and detector is generally referred to as a spectrometer, although the heart of the device is the monochromator. A monochromator is an instrument that... 

Lin et al. 1985 Wade and Meyyappan 1987 Wey and Kessler 1989) the insonification is broadcast throughout the specimen, and the detection is by a focused optical probe that measures local surface tilt on the surface of the specimen. But in the scanning acoustic microscope both the illumination and the detection are performed by focusing elements and, since these are focused at the same point, the configuration may be described as confocal. The first con-focal acoustic microscopes worked in transmission and, although this is now of mainly historical interest, the transmission arrangement will be described first because in some respects it is simpler and will serve to introduce some principles. 

Fig. 2. A magnetooptical player (2). P = polarizer MC = magnetic coil (for magnetooptical writing) NBS = neutral beam splitter PBS = polarizing beam splitter. Dl, D2 = detectors for differential detection. The optical path also comprises tracking and focusing optics which are not shown here.

This lamp also illuminates, through a focusing optical system, a small region of the x-ray diffraction film. The transmitted... 

Fig. 7. Block diagram of laser-induced breakdown spectroscopy experimental setup (A) pulsed laser, (B) focusing optics, (C) microplasma, (D) collection optics, (E) spectrometer, and (F) data analyzer.

The Art- beam was directed into the chemical laser cavity along the optical axis by a focusing optical train. The spot size in the cavity was a fraction of a millimeter, although tighter focusing could have been done, thus increasing the spatial resolution. The Art- beam could be translated in two dimensions, up and down the nozzle face, at a single position in the flow direction, and also downstream from the nozzle face. Hence, the flow field could be visually mapped out. 

Figure 7. Uncalibrated VCD absorbance curves (upper) and ordinary absorbance (lower) for a-pinene. The signs of the enantiomers and the racemic mixture of a-pinene are indicated. The spectra on the left were take with the lens focusing optics and those on the right with the ellipsoidal mirror focusing optics.

Figure 8. Corrected VCD spectra (middle) obtained by subtraction of the spectra of the enantiomers for the lens focusing optics on the left and the mirror focusing optics on the right. Absorbance spectra (bottom) and noise curves (top) are also given.

The mould after the two LADI processes showing no visible damage. The LADI area could be as large as a whole wafer (4 inch or 8 inch diameter). This method eliminates the costs because no expensive focusing optics and resist is needed. 

Are the XAFS data to be collected on an insertion device (ID) or bending magnet (BM) beam line, and what X-ray focusing optics are available The beam line optics should also be taken into account in the design of the cell. If the XAFS data are to be collected on an ID beam line, then, given the naturally small X-ray beam size (less than 1 mm2), the whole reaction cell (or at least the sample size) can be significantly smaller. If the sample is nonuniform, data quality will be more affected on an ID beam line than a BM beam line. 

Another approach is to use focused X-ray beams in the scanning mode. This technique will require specialized focusing optics and a fast monochromator. Such a nanoprobe beam line is currently being developed at the APS and is expected to have the spatial resolution of several tens of nanometers. At the proposed NSLS-II synchrotron, a beam line with a spatial resolution of ten nanometers is planned. With the development of these beam lines, it is expected that spatial imaging will be available for characterization of catalysts, and of course the hope is to do this with catalysts in reactive atmospheres. 

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