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....Optics Highlights | ||
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VIII. Some Roots of Modern Optical Systems |
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| In the 20th Century, revolutionary advances in optics began with the construction of the first laser in 1960 and has led to the rapid development of optical communication systems, imaging systems and holography, optical data storage and retrieval systems, and optical processing. Historically, however, optical communications systems date back to the optical semaphore systems developed by Chappe in France in 1791 and which were widely used in England and the United States during the 19th Century. Imaging systems have their roots in the invention of photography by Niepce in 1826 and stereoscopy by Wheatstone in 1832. The first optical data storage and retrieval system may have been the recording system devised by John Logie Baird in 1925 (followed by a variety of different systems in the 1950’s). Holography was invented by Denis Gabor in 1948. Optical data processing was inherent in the work of Abbe in 1873 and spatial filtering had its origins in the phase contrast technique invented in 1935 by Frits Zernike. | ||||
 Claude Chappe (1763 - 1805) was the grandson of a
French baron and was raised for the church. He lost his
religious sinecures as a result of the Revolution and
along with his four (also now unemployed) brothers turned
to working on a mechanical semaphore system for telegraphy.
They obtained the support of the Revolutionary Convention
and in 1794, after several design changes, succeeded,
despite the violence of the Revolution, in establishing a
chain of fifteen tower stations linking Paris and Lille,
120 miles to the north. France established a national
system which was finally replaced by the electric
telegraph beginning in 1846. In 1804, Claude Chappe,
depressed by illness and by mounting claims of plagiarism
(after all, the military had used semaphore systems)
threw himself down the well at his hotel. |
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 Joseph-Nicéphore
Niepce (1765 -
1833) was the son of a wealthy family and fled France during
the Revolution. He returned to fight in the Napoleonic
army and then retired because of ill health. In 1826, he
was the first to produce a permanent photograph. In 1829
Niepce agreed to a partnership with Louis Daguerre, a
Parisian artist and showman, who eventually improved the
process and reduced the required exposure time from hours
to about 20 minutes. The partnership, which was the
result of Daquerre’s importuning, resulted in very little
benefit for Niepce or his heirs and is often represented
as based on grandiose promises by Daguerre, Niepce’s
age and illness, and the fear of other inventors who were
perfecting chemical processes for photography at the same
time. In 1839, the French Academy bought the patent
rights to the Daguerre process. |
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 (Sir) Charles
Wheatstone
(1802 - 1875) was a Professor at King's College, London,
whose name, which is attached to the circuit he invented
for the newly invented telegraph, is known to all
electrical engineers. In 1838 Wheatstone discovered the
principles of stereoscopic vision and invented the
stereoscope. His viewer was later superseded by a design
due to Brewster. Stereoscopes enjoyed enormous popularity
in Victorian times; Queen Victoria, for example, was a
devoted fan. However, Wheatstone did not profit greatly
from it. (Above we show the design due to Oliver Wendel
Holmes, no less, which was most popular in America.)
Wheatstone and his heirs did profit from his invention
and manufacture of the concertina, however; this small
elegant instrument was all the rage in Victorian drawing
rooms, music halls and Salvation Army bands. |
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 John Logie Baird (1888 -1946) was the son of Scottish minister; as
a boy he showed an early interest in electrical
inventions, creating a number of crises in his hometown, Helensburgh.
After graduating from the University of Glasgow, he
worked as an engineer for a Glasgow electrical company,
but was discharged when he blacked out half the city in an
unauthorized experiment to create diamonds. In the
1920’s Baird began working on television using the
Nipkow mechanical scanning disk invented in 1884. In 1926
he demonstrated the first television. He went on to
demonstrate the first color and stereo televisions and
succeeded in recording his video signals on disks. From
1929 to 1935, the BBC used the Baird mechanical television
system; in the last part of this period, it shared time
with the electronic system. |
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 Denis Gabor (1900-1979) was born in Budapest
and worked as a research engineer in Berlin from 1927 to
1933 when he fled to England and worked for the
Thomson-Houston company. In 1947, in an attempt to
improve electron microscopy, and possibly influenced by
Bragg’s work on x-ray crystallography, Gabor
invented the basic wave-front reconstruction technique of
holography. Contemporary light sources were inadequate
and it was not until the invention of the laser in 1960
and the invention of the off-set holographic technique by
Leith and Upatnieks in 1962 that the potential of
holography was realized. Thus it was not until 1971 that
Gabor received the Nobel Prize for his 1947 invention |
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 Frits Zernike (1888-1966) was a professor at the
University of Groningen from 1915 to 1958. In a study of
diffraction gratings, he noted that he was able to
discern materials of different refractive indices despite
their transparency, and discovered the phase contrast
principle. Although other optical techniques, e.g.,
shadowgraph and schlieren, could also do this, the phase
contrast technique provides a linear relation between
phase retardation and image intensity. Zernike built a
microscope based on the principle in 1938 and received
the Nobel Prize in 1953. |
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