Experiment 4: The Michelson Interferometer Mar. 30, 2016 Ivan Bai Rick Feng Objective: a) To determine the wavelength of a laser light source, and b) the index of refraction of air at atmospheric pressure. Theory: This lab is to use a Michelson’s interferometer to measure the wavelength of light, for using the wavelength of a known light source to measure extremely small distances, and for investigating optical media. According to the principle of superposition, a beam can be modeled as a linear system where the input stimulus is the load on the beam and the output response is the deflection of the beam. That is, at each point in space, the electric and magnetic fields are determined as the vector sum of the fields of the separate beams. If the beam of light originates from a separate source, there is no fixed relationship between the electromagnetic oscillations in the beams. A uniform intensity of light can be seen by the human eye. If the beams of light originate from the same source, there is generally some degree of correlation between the frequency and phase of the oscillations. Therefore, the light from the beams may be continually out of phase and so a minimum, or a dark spot, will be seen. By using the Michelson interferometer, the beam of light from the laser can be split into two beams: one beam is transmitted toward the movable mirror and the other is reflected toward the fixed mirror. Both of the beams are reflected from the beam-splitter to the viewing screen. Since the two interfering beams of light were split from the same initial beam, they were initially in phase. Their relative phase depends on the difference in the length of their optical paths in reaching that point on the viewing screen. By slowly moving the mirror a distance d m
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- Spring '09
- Light, Michelson interferometer, Michelson, fringe, Ivan Bai