Optical Physical Principles

The nonlinear optical teclmiques of up- and down-conversion are based on mixing optical beams in a suitable crystal (BBO, LiNbO, KDP, etc) witli tire generation of new optical frequencies tire physical principle is as follows. If two beams having optical frequencies cOp CO2 and wavevectors k, are mixed in a nonlinear optical crystal at tire appropriate angle, a new optical frequency co can be coherently generated witli tire following conditions satisfied ... 

The optical method is interesting not so much for any practical use in solving structures or performing Fourier synthesis as for its educative and demonstrative value it makes clear the physical principles of image formation. 

The sizing methods involve both classical and modem instrumentations, based on a broad spectrum of physical principles. The typical measuring systems may be classified according to their operation mechanisms, which include mechanical (sieving), optical and electronic (microscopy, laser Doppler phase shift, Fraunhofer diffraction, transmission electron miscroscopy [TEM], and scanning electron microscopy [SEM]), dynamic (sedimentation), and physical and chemical (gas adsorption) principles. The methods to be introduced later are briefly summarized in Table 1.2. A more complete list of particle sizing methods is given by Svarovsky (1990). 

I feel it would have been premature to use the new term chemical interference, which combines all types of synchronized complex reactions, in the title of this book, because the term interference is usually associated with optics. This involves efforts to find something analogous to physical (optical) interference principles in complex chemical systems. 

Measurements of liquid density are closely related to quantity and liquid-level measurements since both are often required simultaneously to establish the mass contents of a tank, and the same physical principle may often be used for either measurement, since liquid-level detectors sense the steep density gradient at the liquid-vapor interface. Thus, the methods of density determination include the following techniques direct weighing, differential pressure, capacitance, optical, acoustic, and nuclear radiation attenuation. In general, the various liquid level principles apply to density measurement techniques as well. 

Look up and then describe the physical principles on which the operation of the following thermometers is based (a) semiconductors, (b) paramagnetic salts, (c) optical pyrometers, (d) thermocouples. 

TTiis review attempts to survey second-order molecular polarizabilities of organic molecules. Emphasis will primarily be given to the underlying physical principles of non-linear optics (e.g. molecular topology), and to the establishment of structure-property relationships. We will largely remain paradigmatic and will not attempt an exhaustive compilation of data because several good review articles and books exist that incorporate tabulations of numerous... 

The photon echo phenomenon is perhaps the most dramatic manifestation of using physical principles to overcome what appears to be the erasure of molecular information caused by inhomogeneous broadening. The effect was first demonstrated by Hahn in NMR spectroscopy (Phys. Rev. 80, 580 (1950)) and extended to optical spectroscopy by Kemit, Abella and Hartmann (Phys. Rev. Letters, 13, 567 (1964)).21 Here we only outline its basic physical principle. 

The rates of change (slopes of the curves) of many important properties (such as the refractive index, surface tension, and gas permeabilities) as a function of temperature, the value of the dielectric constant, and many other optical and electrical properties, often change considerably at Tg. These changes enable the measurement of Tg by using techniques such as refractometry and dielectric relaxation spectroscopy. Refractometry provides results which are similar to those obtained from dilatometry, because of the correlation between the rates of change of the specific volume and of the refractive index with temperature. Dielectric relaxation spectroscopy is based on general physical principles which are similar to those in dynamic mechanical spectroscopy, the main difference being in its use of an electrical rather than a mechanical stimulus. 

Vector and Tensor Analysjst G. E. Hay. 2.00 Optical Properties of Thin Solid Films, O. S. Heavens. 2.75 The Physical Principles of the Quantum Theory, Werner Heisenberg. 1.50... 

The nonlinear optieal teehniques of up- and down-eonversion are based on mixing optical beams in a suitable erystal (BBO, LiNbOg, KDP, etc) with the generation of new optical frequencies the physical principle is as... 

Different techniques for manipulating cells in microfluidic devices have been proposed for a wide variety of applications. The purpose of this essay is to systematize the techniques by the physical principles and forces used for controlling cell position. The reader is encouraged to follow the links to chapters describing in more detail how the interaction between cells and mechanical and biochemical entities or with electric, magnetic, or optical fields can be implemented at microscale for the handling of cells for various applications (Table 1). 

After dealing in some detail with the optical and transport properties of amorphous semiconductors, we include a chapter on some of their applications in practical devices. We believe that it is of general interest to the reader to learn about the physical principles of various devices based on amorphous semiconductors. It should sJso be a stimulating reading on a field whose future depends much on further ingenuity in applied research. This remark does not mean that a deeper understanding of the fundamentals should be underestimated. It is well known what a difference it made in the crystalline semiconductor technology in the fifties compared with the thirties. 

More detailed information regarding the physical principles of fiber-optical chemical and biochemical sensors and the corresponding detection systems is available in [166] and [167]. 

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