Michelson_interferometer

1. Assignment of physics
Submitted by- Twinkle
sharma
course- B.Tech(general)
Submitted to- Chitra
manro

2. content
 INTERFERENCE
 INTERFEROMETER
 MICHELSON INTERFEROMETER
 FIGURE
 CONSTRUCTION
 WORKING
 APPLICATIONS AND USES
 LIMITATION
 BIBLIOGRAPHY

3. INTERFERENCE

4. INTERFEROMETER
THE MICHELSON INTERFEROMETER IS A COMMON CONFIGURATION FOR OPTICAL
INTERFEROMETRY AND WAS INVENTED BY THE 19/20TH-CENTURY AMERICAN PHYSICIST ALBERT
ABRAHAM MICHELSON. USING A BEAM SPLITTER, A LIGHT SOURCE IS SPLIT INTO TWO ARMS.
EACH OF THOSE LIGHT BEAMS IS REFLECTED BACK TOWARD THE BEAM SPLITTER WHICH THEN
COMBINES THEIR AMPLITUDES USING THE SUPERPOSITION PRINCIPLE. THE RESULTING
INTERFERENCE PATTERN THAT IS NOT DIRECTED BACK TOWARD THE SOURCE IS TYPICALLY
DIRECTED TO SOME TYPE OF PHOTOELECTRIC DETECTOR OR CAMERA. FOR DIFFERENT
APPLICATIONS OF THE INTERFEROMETER, THE TWO LIGHT PATHS CAN BE WITH DIFFERENT
LENGTHS OR INCORPORATE OPTICAL ELEMENTS OR EVEN MATERIALS UNDER TEST.

5. MICHELSON INTERFEROMETER
 A Michelson interferometer is a tool to produce interference between
two beam of light . It is a most common device for optical
interferometry, and it was invented by Albert Abraham Michelson.
 A Michelson interferometer produces interference fringes by splitting a
beam of monochromatic light ,such that when one beam hits a fixed
mirror and other hit a movable mirror . When the reflected beams are
combined ,an interference pattern is formed .
 To create interference fringes on a detector , the paths must be of
different lengths or composed of different materials.
 Michelson interferometer are relatively simple in operation and passes
the largest field of view for specified wavelength . They also posses a
relatively low temperature sensitivity.

6. FIGURE

7. CONSTRUCTION
 The main optical parts consist of highly polished mirror A1 and A2
and a plane parallel plate of glass G1 ( COMPENSATOR PLATE) and
G2 a beam splitter.
 Sometimes the rear side of beam splitter is lightly silvered , so that
light coming from source is divided into 1(a) reflected and 2(b) a
transmitted beam of equal intensity.
 To obtain the interference fringes the mirror A1 and A2 are made
exactly perpendicular to each other.

8. WORKING
 Light from a source strikes partially silvered beam splitter , causing part of the beam to be
transmitted towards a mirror A1, to movable carriage .
 The remainder of beam is reflected from a beam splitter toward a fixed mirror, A2 . A glass
compensation plate along the path towards A1 ensures that the two paths are effectively
identical.
 The two beams, once reflected from A1 and A2 , re-converge at the beam splitter.
 A precision micrometer is connected to A1 carriage and allows the optical path length along the
M1 branch to be over a few mm. Fine adjustment screws on A2 allow fine tunning such that the
beams from each branch can be overlapped at the viewing screen
 When recombined and aligned, the beams falls on the interferometer’s viewing screen where
the resultant light exhibits interference effects dependent on the light differences between
the two paths.
 If the distance from the beams splitter to mirrors A1 and A2 differ by distance d , then the
total difference in the path lengths travelled by two beams of light is 2d.
 When the distance 2d is equal to an integer multiple of the light wavelength, constructive
interference is observed at the viewing screen as the crests of the two beams overlap, and a
bright spot or ring is seen as the viewing screen

9. APPLICATIONS OF MICHELESON
INTERFEROMETER
THE REFRACTIVE INDEX OF A THIN FILM.
WAVELENGTHOF MONOCHROMATIC LIGHT.
RESOLUTIONOF SPECTRAL LINES.
THE EVOLUTIONOF METERS IN TERMS OF THE WAVELENGTHOF LIGHT.
THE ANGULARDIAMETER OF STARS.
 PRESENCE OF ETHER.
 THE ACCURACY OF THE SURFACE OF THE PRISM AND LENS.

10. LIMITATIONS
 Unable to get accurate readings especially for white light (require precise
control of the beam paths.)
 To get around this one can use cube corner mirrors and the four – part design
but that makes it more expensive.
 Reflects 50% of light back to the source ,reducing the reliability of
measurements made.

11. BIBLIOGRAPHY
• STEEL, W. INTERFEROMETRY. CAMBRIDGE CAMBRIDGESHIRE NEW YORK:
CAMBRIDGE UNIVERSITY PRESS, 1983.
• SERWAY, RAYMOND. COLLEGE PHYSICS. BELMONT, CALIF. LONDON: BROOKS/COLE
CENGAGE LEARNING DISTRIBUTOR, 2008.
• ARULDHAS, G. MODERN PHYSICS. NEW DELHI: PRENTICE-HALL OF INDIA, 2005.
• WWW.COLORADO.EDU/PHYSICS/PHYS5430/PHYS5430_SP01/PDF%20FILES/MICHEL
SON%20INTERFEROMETER.PDF
• PHYSICS.GMU.EDU/~ELLSWORT/P263/MICHELSON.PDF
• WWW.YOUTUBE.COM/WATCH