Fiber optics

1
8. ?????????????????
2
??????????????? (Fiber optics)
3
n0
Core???? (SiO2 ?????? visible--gtIR)
qc
??????????
q1
1
q0
nf
Cladding (?????????? n ???????? Core)
nc
1
2
3
????
Numerical Aperture N.A.
? (?????????????????????????)2
3
??????????????????????
n
n
n
4
High order
Multi mode fiber gt ?????????????????
???????????????????????????????? ????? --gt
High order mode ???????????????
?????????????????? ??????--gt Low order mode
??????????????? ??????????????????? ??? 0o --gt
Axial mode ????????????????????????? gt
?????????????????????????? gt
?????????????????????????? (intermode dispersion)
??????????????????????????????
5
Multi mode, stepped index fiber gt
??????????????? ?????????????? ?????????????????
?????????????????????????????????????? ??????????
?????????? Multi mode, graded index fiber gt
???????????????????? High order mode
????????? ??????????? n ?????? ?? C ??????? ??
DT Single mode gt ??????????????????????
??????????????????????????????????? ????????????
????????????????????????????????????????
6
?????????(Holography)
??????????????????????????????????????????????????
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?????
Gabor Zone plate
????????????
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???????
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?????????

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• ??????????????????? 3D (??????????????????????????
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7
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rr(x,y) ? ?????
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S, q ? ?????????????????????????
8
???????
??????????????????????????? ?????????????????
?????????????????????? ?????????????? ? IF
9
????????????????????????
????????????
?????????????????
1st order real
1st order virtual
0th order
10
gt 0th order ????????????????????????
????????????
gt 1st order virtual image ????????????????
????????????????????????(
)
gt 1st order real image ????????????????
????? 2a ???????????????
11
(No Transcript)
12
Holography application

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• interferogram (?????????????????)
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13
The biography of Dennis Gabor (1900-1979) "You
can't predict the future, but you can invent it."
- Dennis Gabor
D. Gabor was born in Budapest, Hungary, and his
life-long love of physics started suddenly at the
age of 15. He learned the calculus and worked
through the textbook in the next two years. With
his late brother George, they also built up a
little laboratory in their home, where they could
repeat most experiments which were modern at that
time, such as wireless X-rays and radioactivity.
He acquired his degrees in electrical
engineering in High Technical School, Berlin
(Diploma in 1924, Dr-Ing. in 1927). Though
electrical engineering remained his profession,
his work was almost always in applied physics.
His doctorate work was the development of one of
the first high speed cathode ray oscillographs.
In 1927 D. Gabor joined the Siemens Halske AG
where he made his first successful inventions
the high pressure quartz mercury lamp with
superheated vapor and the molybdenum tape seal,
since used in millions of street lamps. In 1933,
when Hitler came to power, Gabor left Germany and
after a short period in Hungary went to England,
where obtained employment with the British
Thomson-Houston Co., Rugby.
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The years after the war were the most fruitful.
He wrote, among many others, his first papers on
communication theory, developed a system of
stereoscopic cinematography, and in 1948 carried
out the basic experiments in holography, at that
time called "wavefront reconstruction". Then,
until his retirement in 1967, he improved Wilson
chamber, developed holographic microscope, a new
electron-velocity spectroscope, flat thin color
television tube. Theoretical work included
communication theory, plasma theory, magnetron
theory. In 1971 Dr. Dennis Gabor was awarded
the Nobel Prize in Physics for his discovery of
holography in 1947. But, in his own words We
had started 20 years too early. Only in recent
years have certain auxiliary techniques developed
to the point when electron holography could
become a success. On the other hand, optical
holography has become a world success after the
invention and introduction of the laser.