Emil Wolf talks with
ScienceWatch.com and answers a few questions about
this month's Emerging Research Front Paper in the field of
Article: Unified theory of coherence and
polarization of random electromagnetic
Journal: PHYS LETT A, 312 (5-6): 263-267 JUN 16 2003
Addresses: Univ Rochester, Dept Phys & Astron, 601
Elmwood Ave, Rochester, NY 14627 USA.
Univ Rochester, Dept Phys & Astron, Rochester, NY 14627
Univ Rochester, Inst Opt, Rochester, NY 14627 USA.
Why do you think your paper is highly
Because the theory presented in that paper makes it possible to provide
solutions to a number of scientific, technological, and medical problems
which could not have been done previously.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
The discovery reported in the paper provides a synthesis of two branches of
optics, known as the theory of coherence and the theory of polarization of
light. Until the publication of my paper, these two subjects had always
been treated independently of each other. Prior to the invention of the
laser, almost 50 years ago, the available sources which generate light,
such as a light bulb and the sun, may be shown to have, on a short time
scale, irregularities (called fluctuations) which make it impossible to use
such light for some applications. Light of this kind is said to be
"I have carried out research
regarding coherence for most of my scientific
career which now extends over more than 50
On the other hand, laser light is said to be coherent, has a much more
regular behavior and also is very intense. This makes it possible to
utilize it for many different purposes. For example, it is used in
ophthalmology for treating some eye disorders such as detached retinas and
cataracts; it is used to record and play music; and it has an important
role in the operation of computers and supermarket barcode readers at the
checkout counters. Roughly speaking, coherence theory is concerned with
analyzing the effects of fluctuations.
Another aspect of these fluctuations is known as polarization, a phenomenon
utilized, for example, in certain kinds of eyeglasses and in automobile
headlights to reduce glare.
Would you summarize the significance of your paper in
Until the publication of my paper, coherence and polarization were treated
independently of each other. I showed that they are actually intimately
related. This discovery makes it possible to solve many problems which were
not solvable before.
How did you become involved in this research and were
any particular problems encountered along the way?
I have carried out research regarding coherence for most of my scientific
career which now extends over more than 50 years. About six years ago, I
started writing a book on the coherence properties of light. In the process
of writing it, I had to examine some features of polarization, and after
researching it, I discovered the intimate relation between these two areas
of optics that has led to the publication of this highly cited paper and
also to many papers published on the subject since then. The book, which
was published by Cambridge University Press in 2007, and is entitled
Introduction to the Theory of Coherence and Polarization of Light,
presents an account of the new theory and discusses some of its
Where do you see your research leading in the
I expect that many applications of the theory will be forthcoming. Some
have already been made; they answer questions to some old problems, such as
an elucidation of the effects of atmospheric turbulence on the propagation
of light through the atmosphere, a subject which is of importance in
communications via GPS guidance systems. Another application may well be
found in medical diagnostics, particularly in connection with abnormalities
in biological tissues. Clarification of some aspects of the propagation of
light through optical fibers, which are also used for communication, are
also likely to be forthcoming.
Do you foresee any social or political implications for
This research has been supported by the Air Force Office of Scientific
Research (AFOSR), located in Arlington, Virginia. I presume that they may
be interested in some of the applications I've mentioned; and possibly even
in some which might still be forthcoming. As regards social implications, I
think that in a broad sense the technological and medical applications
which I've already mentioned touch upon this subject.
Wilson Professor of Optical Physics
Department of Physics & Astronomy
University of Rochester
Rochester, NY, USA Web
KEYWORDS: LIGHT, UNIFIED THEORY, RANDOM ELECTROMAGNETIC