Optical design

Each type of mass spectrometer has its associated advantages and disadvantages. Quadrupole-based systems offer a fairly simple ion optics design that provides a certain degree of flexibility with respect to instrument configuration. For example, quadrupole mass filters are often found in hybrid systems, that is, coupled with another surface analytical method, such as electron spectroscopy for chemical analysis or scanning Auger spectroscopy. 

The Mattauch-Herzoggeometry (Fig. 3.20) enables detection of several masses simultaneously and is, therefore, ideal for scanning instruments [3.49]. Up to five detectors are adjusted mechanically to locations in the detection plane, and thus to masses of interest. Because of this it is possible to detect, e. g., all isotopes of one element simultaneously in a certain mass range. Also fast, sensitive, and precise measurements of the distributions of different isotopes are feasible. This enables calculation of isotope ratios of small particles visible in the image. The only commercial instrument of this type (Cameca Nanosims 50) uses an ion gun of coaxial optical design, and secondary ion extraction the lateral resolution is 50 nm. 

In an excellent historical overview of these stages and the intellectual and practical problems which had to be overcome, Mulvey (1995) remarks that the first production microscopes pursued exactly the same electron-optical design as Ruska s first experimental microscope. The stages of subsequent improvement are outlined by Mulvey, to whom the reader is referred for further details. 

CVD/PVD thin films are usually considered as coatings having a thickness of less than ten microns. This is an arbitrary limitation and perhaps a better definition would be a coating that adds little if any mass to the substrate. Most thin films, in fact, are much less than 10 im and may be even less than 0.2 im in the newer semiconductor and optical designs, while some wear and erosion applications can be much thicker than 10 im. 

We present the basics of optical design as it applies to two mirrored telescope systems. We discuss Zemike decomposition of wave-front error and the description of Strehl in terms of small Zemike errors. We also discuss the balancing of aberrations for a two mirror system and present the Ritchey-Chrdtien design as an example of a zero coma system. 

Two-mirror telescopes are the most common optical design for ground based telescopes. These systems require a parabolic or hyperbolic primary mirror. As mentioned before, more complex optical systems can accommodate a spherical primary with its attendant simplifications, but several additional mirrors are needed to correct the spherical aberration, and the light loss and alignment complexity makes this configuration less commonly used. Here we will assume that a non spherical primary is needed and we will discuss the resulting surface shapes that segments will have. 

The OWL optical design is shown in Fig. 1. It is based on a spherical and flat folding secondary mirrors, with a four-element corrector providing for the compensation of spherical and field aberrations as well as advanced active optics and dual-conjugate adaptive optics. A complete discussion would exceed the scope of this report we shall however mention a few key arguments supporting this solution ... 

Besides the increase of reflections implied by Owl optical design, a price to pay for the spherical primary mirror solution is the difficulty to compensate for its spherical aberration, and in particular the horrendous aspherization of the quaternary mirror (which is conjugated to the primary). A possible test setup has been identified and the state of current technology allows for cautious hope industrial studies are however still required to confirm feasibility and evaluate implied cost and schedule. 

Dierickx, P.,2001, Optical design and adaptive optics properties of the OWL 100-m telescope] ESO Conf. Beyond Conventional Adaptive Optics, Venice, (http //lenin.pd.astro.it/venice2001/proceedings/)... 

Our group is involved since several years in ESA s studies of the NIRSPEC instrument. We have focused our work on three main topics MMA and MSA modeling, characterization of the MMA and MSA, and optical design for the MOS (Zamkotsian et al., 1999 Zamkotsian et al., 2000a). 

Terenziani F, D Avino G, Painelli A (2007) Multichromophores for nonlinear optics designing the material properties by electrostatic interactions. Chemphyschem 8 2433-2444... 

Optical designers and specialists in heat transfer calculations in the chemical engineering and mechanical engineering sciences are familiar with the mathematical construct known as The Equation of Radiative Transfer, although most chemists and spectroscopists are not. The Equation of Radiative Transfer states that, disregarding absorbance and scattering, in a lossless optical system... 

Figure 4. The sample cell arrangement in the DCSHG experiment, where the sample solution was inserted between two glass slips (lop), and the optical design for the DCSHG dispersion experiment, where the compressed H gas medium was pumped by a tunable pulsed dye laser source for Stokes generation by stimulated Raman scattering (bottom). (E° is the static electric field.) Key beam guiding prisms P, Stokes...

OTHER PROBLEMS LINKED TO HARDWARE OR OPTICAL DESIGN... 

F.R. Zhu and J. Singh, On the optical design of thin film amorphous silicon solar cells, Sol. Energy Mater. Sol. Cells, 31 119-131, 1993. 

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