Thin Film Interference
http://graphics.ucsd.edu/~iman/SoapBubbles/
Color ADDITION (light)
?
2?
1?
3R
ef
le
ct
s
G
re
en
/
B
lu
e
A
bs
or
bs
R
E
D
Reflects
Green
/
Red
Absorbs
BLUE
Color SUBTRACTION (pigments)
¾ λ
½ λ
¼ λ
http://www.trivalleystargazers.org/gert/rc10_testing/RC10_testing_M2.html
¼
¾
1¼
1¾
2¼
λ
green= 532 nanometers
2(.000000532) meters
.000001064 meters
Monochromatic Light
λ
green= .000000532 meters
The clip is made of Nickel.
When heated with a torch, the Nickel on the surface reacts with the Oxygen in the air.
Nickel Oxide is formed.
n = 1.35
n = 1.00 n = 1.00
λ = 532 nm λ = ? nm
v = f·λ
3 x 108 = f · 532x10-9
f = 5.64 x 1014 Hz
n = c/v
1.35 = 3 x 108 / v
v = 222,000,000 m/s
222,000,000 = 5.64x1014 ·λ
v = f·λ
λ = 3.94 x 10-7 λ = 394 nm
Ends of Medium
FREE
Ends of Medium
FIXED
FLEXIBLE
RIGID
No PHASE change!
Ends of Medium
FREE
Ends of Medium
FIXED
FLEXIBLE
RIGID
No PHASE change!
180 PHASE change!
Smaller Index of Refraction
Larger Index of Refraction
n = 3.5
n = 1.2
n = 1.2
n = 1.0
n = 1.0 n =1.2
n = 1.5
n = 1.3
n = 1.0
1 ¼ λ
1 ¼ λ
Air Oil Water
Air Glass Air
n = 1.0
n = 1.0 n =1.2
n = 1.5
n = 1.3
1 ¼ λ
1 ¼ λ
Air Oil Water
Air Glass
n = 1.0
Air No PHASE change! 180 PHASE change! Smaller Index of Refraction Larger Index of Refraction
1 ½ λ
P H A SE c h an ge ! N O P H A SE c h an ge ! PHASE change! P H A SE c h an ge ! P H A SE c h an ge ! PHASE change! NO PHASE change!
1 ½ λ
Air n = 1.0
SiO n = 1.45
Air n = 1.0
SiO n = 1.45
1638
More than 10 times the
speed of sound
Galileo Galilei
1564 -1642
http://fr.questmachine.org/encyclopedie/Page_image.php?image=/encyclopedie/ illustrations/illustrations_articles/H4180288-Olaus_Roemer-SPL.jpg
Olaus Roemer
(1644-1710)
1675
227,000,000 m/s
First Estimate of the Speed of Light
Period = 1.769138 days = 2,547.559 minutes = 152,853.5 seconds
Io
Distance
V =
d
t
=
186,000,000 mi
22 min
·
60 sec
1 min
·
1609 m
1 mi
= 227,000,000 m/s
23% E of D
Actual time = 17 min
Period = 1.769138 days = 2,547.559 minutes = 152,853.5 seconds
206 revolutions in 6 months Off by 5 minutes over 6 months Off by 1.46 seconds per revolution
1862
299,796,000 m/s
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James Clerk Maxwell
𝑐
=
1
√
μ
𝑜
ε
𝑜
𝑐
=
𝐸
𝐵
http://www.srh.noaa.gov/jetstream/remote/images/emwave.gif
The speed of light is a CONSTANT 2.998 x 108
m/s
1864
paper "Electromagnetic theory of light"¿
1
30 m
1 m/s
4 m/s
4 m/s
5 m/s going, (6 seconds)
3 m/s coming back, (10 seconds)
4 m/s going, (7.5 seconds)
http://www.aip.de/~lie/Bi/Michelson.050617.4.jpg
http://kenolab.com/images/Interferometer/green_fringes.jpg
L
aser
I
nterferometer
G
wave
O
bservatory
February 11, 2016
