Michelson_Interferometer.pptx

Michelson_interferometer

1. MICHELSON INTERFEROMETER 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. Wavelength of monochromatic light. Resolution of spectral lines. The evolution of meters in terms of the wavelength of light. The angular diameter 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/Michelson%20Interferometer.pdf physics.gmu.edu/~ ellswort /p263/michelson.pdf   www.youtube.com/watch