Dictionary of Pure and Applied Physics

383 Pages·2016·50.99 MB·English

by  Basu D.K. (Editor)

A VOLUME IN THE
COMPREHENSIVE DICTIONARY
OF PHYSICS
C>F
~ICTIC>~~Y-
PURE
AND
APPLIED
PHYSICS
Edited by
Dipa1<Basu
CRCPress
Boca Raton London New York Washington, D.C.
or
Library Congress Cataloging.in.Publiclllion Oala
DiClionlry or pure Ind apphd phy,ics I ellitai by Dlp:.k Il:r.su
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Preface
The Dictionary of Pure and Applied Physics (DPAP) is one of three physics dictionaries being
published by CRC Press LLC, the other two being the Dictionary of Material Science and High En
ergy Physics and Dictionary of Geophysics, Astrophysics and Astronomy. Each of these dictionaries
is entirely self-contained.
The aim of the DPAP is to provide students, researchers, academics and professionals in general,
with definitions in a very clear and concise form. The presentation is such that readers will not have
any difficulty finding any term being looked for. Each definition is written in detail as informative
as possible supported by suitable diagrams, equations, and formulae whenever necessary.
With more than 3000 terms, the fields covered in the DPAP are acoustics, biophysics and med
ical physics, communication, electricity, electronics, geometrical optics, low temperature physics,
magnetism, and physical optics.
Like most other branches of science, physics has grown rapidly over the last decade. As such,
many of the terms used in older books have become obsolete and new terms have appeared in
scientific and technical literature. Care has been taken to ensure that old terms are not included in
the DPAP and new terminologies are not missed. Some of the terms are related to other fields, e.g.,
engineering fields (mostly electrical and mechanical), mathematics, chemistry, biology.
Authors are eminent scientists at research institutions and university professors from around the
world. Readership includes physicists and engineers in all fields, teachers and students in physics
and engineering at university, college and high school levels, technical writers and professionals in
general.
The uniqueness of the DPAP lies in the fact that it is an extremely useful source of information
in the form of meanings of scientific terms presented in a very clear language and concise form
written by authoritative persons in the field. It would be a great aid to students in understanding
textbooks, help academics and researchers fully appreciate research papers in professional scientific
journals, provide authors in the field with assistance to clarify their writings and, in general, benefit
the enhancement of literacy in physics by presenting scientists and engineers with meaningful and
workable definitions.
DipakBasu
©2001 CRC Press LLC
CONTRIBUTORS
Barry I. Barker Douglas M. Gingrich
Stanford University University of Alberta
Stanford, California Edmonton, Alberta, Canada
DipakBasu Arthur A. Grossman
Carleton University University of California, San Diego
Ottawa, Ontario, Canada San Diego, California
Christopher Boswell Shirin Haque-Copilah
The Johns Hopkins University University of the West Indies
Baltimore, Maryland St. Augustine, Trinidad, West Indies
H.R. Chandrasekhar Takafumi Hayashi
University of Missouri The University of Aizu
Columbia, Missouri Fukushima, Japan
David Cheeke Cila Herman
Concordia University The Johns Hopkins University
Montreal, Quebec, Canada Baltimore, Maryland
Shenlin Chen Stanley Jeffers
Boise, Idaho York University
Toronto, Ontario, Canada
Lee Chow Joe Khachan
University of Central Florida University of Sydney
Orlando, Florida Sydney, NSW, Australia
T.e. Choy Vasudevan Lakshminarayanan
University of Melbourne University of Missouri, St. Louis
Parkville, Victoria, Australia St. Louis, Missouri
J.M. Collins ScottA. Lee
Marquette University University of Toledo
Milwaukee, Wisconsin Toledo, Ohio
Luis Cruz-Cruz Mirko Mirkov
Boston University Cynosure, Inc.
Boston, Massachusetts Chelmsford, Massachusetts
Robert T. Deck Michael J. O'Shea
University of Toledo Kansas State University
Toledo, Ohio Manhattan, Kansas
Vijai Dixit Vladimir Ostashev
St. Louis University NOAA
St. Louis, Missouri Boulder, Colorado
©200l CRC Press LLC
A.G. Uni} Perera Kenneth Trantham
Georgia State University Arkansas Technology University
Atlanta, Georgia Russellville, Arkansas
Edward Rothwell Kainam Thomas Wong
Michigan State University The Chinese University of Hong Kong
East Lansing, Michigan Shatin, NT, Hong Kong
©200l CRC Press LLC
Editorial Advisor
Stan Gibilisco
Acknowledgments
The following figures have been reproduced by kind permissions as mentioned.
Kellner Schmidt optical system: Fundamentals of Optics (4th Edition), by F. Jenkins and H.
White, McGraw Hill, New York, 1976.
Tangential and sagittal focal lines: Mirrors, Prisms and Lenses, by J. P. Southall, Dover Publishers,
New York, 1964.
Lummer-Gehrke plate: Fundamentals of Optics (4th Edition), by F. Jenkins and H. White, Mc
Graw Hill, New York, 1976.
Moira fringes: McGraw Hill Dictionary of Scientific and Technical terms (5th Edition), by S. P.
Parker (Editor-in-Chief), McGraw Hill, New York, 1994.
Heat capacity for 4He. The Lambda phenomenon: John Lipa and Joel Nisser of Stanford Uni
versity.
©2001 CRC Press LLC
rays from the object and the image, hI and h2
the object and image heights, nl and n2 the re
A fractive indices, then the Abbe's sine condition
is
Abbe number Dispersion or separation of ABCD law If qin and qout are the complex
neighboring wavelengths by transparent mate radii of curvature of the input and output beams
rial can be characterized by the Abbe number. of an optical system, they are related by the ele
If for a given material nD, nF, and nc refer to ments of the ABCD matrix according to ABeD
the refractive indices for the FraunhOfer D (589 Iaw.· qout = CA qqiinn++DB · S ee ABCD mat f·IX .
nm), F (489 nm), and C (656 nm), then the
chromatism of the material is characterized by ABCD matrix The height (y) and angle (ae)
its v-value or constringence of a paraxial ray (measured with respect to the
optical axis) can be described by a simple 2 x 2
v= composite system matrix as it passes through
nF -nc an optical system with several elements (lenses,
mirrors, etc.). The elements of the matrix (M)
This is called the refractive efficiency, v-value
are referred to as A, B, C, and D. In the equa
or Abbe number. The larger the constringence,
tion
the lesser the chromatism. The inverse of the
Abbe number is the dispersive power.
~~ ~:
[ ] = M [ ] ; M = MnMn-l
Abbe sine condition (1) For an optical sys
tem, if one considers the object and image planes [~ ~]
Ml =
perpendicular to the optical axis, and 8 to be the
angle relative to the axis made by a ray from an
axial object point in object space of index nand the subscripts i and f refer to the initial (input)
8' to be that in image space of index n', then the and final (output) rays and the system matrix M
transverse magnification, m: is a product of the ray matrices of each element
of the optical system. The optical element clos
nsin8 est to the initial ray has the matrix Ml and the
m = ---:--:---::c- for all 8 and 8' .
n' sin 8' one closest to the final ray has Mn. The physical
significance of the elements of the system matrix
For an object at infinity:
is the following: The input (output) plane cor
responds to the first (second) focal plane when
sin 8' = _J!.... D(A) is equal to zero. The output plane is the
l'
image° pl ane conjugate to the input plane when
where y is the height of a ray parallel to the axis B = with A being the linear magnification.
and f' is the back (or secondary) focal distance. When C = 0, a parallel bundle of input rays
The condition is valid for a lens free of coma and emerges as a parallel bundle of output rays; D
the relationships hold to a good approximation corresponds to the angular magnification. See
in most lenses, but not where discontinuities ap cardinal points.
pear in ray behavior (such as Fresnel lenses or
zone plates). Deviations from this relationship aberration Optical systems form distortion
are called the "offense against the same condi free images when the rays entering the system
tion" and are associated with coma. are parallel to the axis and are close to it (parax
(2) The condition satisfied by rays refracted ial rays). However, this restriction leads to low
by spherical interfaces of an optical system (e.g., throughput. Off-axis and non-paraxial rays lead
microscope) to form an image free of coma; if to distortions which can be classified as (a) chro
8 and 8 are the angles made by non-paraxial matic and (b) monochromatic aberrations. See
1 2
©2001 CRC Press LLC
aberration, chromatic and aberration, mono~ least confusion. The spherical aberration is zero
chromatic. for an optical system if the objcct and image arc
arranged to be at the conjugate poirus of one an
aberr-dtion, chromatic The refractive index othcr. (See conjugate points.) For a thin lens, if
of a material is dependent on wavelength. By the shape is such that the radius of curvature of
Snell's Law, light rays of different wavelengths the first convex surface is about six timc.<; that of
will be refracted at different angles, since index the second concave surface, then the spherical
is not a constant. Because the index of refraction aberration is minimized. The meniscus shape
is higher for shorter wavelengths, these are fo of eyeglasses is chosen for Ihis reason, Optical
cused closer to a lens when compared to longer systems such as cameras can reduce this defect
wavelengths, when polychromatic or white light by using smaller apertures (large f-numbers) to
is incident on it. L.ongitudinal chromatic aber~ block off the outer rays.
ration is defined to be the axial distance from
the ncarest to the farthcst focal points.
M"'lIi ..l ta)'>
aberr-dtion,lateral The inability of a system Circle onUsl
"""fu,ion
to focus mys [rom a source on its axis to a point
Poroxiol ta)~ ,
on the axis. but instead focus at a point shifted
-
perpendicularly or laterally to the axis.
I.onQ;n>dinal
abernttion,longitudinal When a system fo Sphericol
A"",,""
cuses the obliquely incident rays on the optical
axis but at a point that is nOlthe focal point for Aberration, spherical.
the paraxial rays.
abernttion or optical systems Any error in aberrutions, Seidel Monochromatic aber-
imaging, for example due to dispersion (ehro~ rations named after the Gennan mathematician
matic), curvature of the surface (spherical), Ludwig von Seidel who studied aberration the
coma, astigmatism, distortion. etc., resulting in ory keeping higher order tenns for parameters
inability of an optical system to bring a broad describing the departure of thc incident beam
beam to focus at a unique point. from a paraxial beam, The five Seidel aberra
tions arc astigmatism, coma. curvature of field.
abernations, monochromatic 11le aberra~ distortion, and spherical aberration.
tions in an optical system even for a monochro
matic light. thus arising totally from thc geome~ abrupt junction A diode junction in which
try of the system. in contrast to chromatic aber+ the dopant level or material type changes
ration (see chromatic aberration) due to disper abnlptly at the junction.
sion of the medium (dilTerent refractive indices A diode is fonned at the junction of two ma
for different wavelengths of the incident light). terials with different Fenni levels (that is. each
with a di[ferent chemical potential. the energy
abernttion, spherical This distortion is level which is the highest filled at a temperature
caused by marginal or non-paraxial rays (i.e., of absolute zero). In semiconductors, one way
rays that are parallel to the axis but are further to alter the Fenni level of the material is to add
from the axis). The image hasadilTuse halo sur dopanl~ that arc either elcctron donors or ae·
rounding the sharp image fonned by the paraxial eeptors. A diode constructed of the same basic
rays. The marginal rays come to a focus at dif semiconductor material call be rcali;o;ed with dif·
ferent points on the axis compared to paraxial ferent dopants on each side of the junction. The
rays and divcrgc at stecper angles. (See dia dopant level can be changed gradually across
gram.) This leads to longitudinal and transverse the device, or change abmptly at the junction.
spherical aberration. The position at which the In real devicc.<;, the dopant level changes in a re
image blur is minimum is called the circle of gion small compared to the depletion layer. the
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