# How the interferometer produces straight line and circular fringes?

## How the interferometer produces straight line and circular fringes?

Schematic representation of a Michelson interferometer to generate interference fringes of different shapes (a) generates circular fringes when the observation point lies on a line perpendicular to the line joining the two sources of light, i.e., when two mirrors are parallel to each other and (b) generates straight or …

## What would be the fringe pattern in Michelson interferometer when the mirrors M1 and M2 are in wedge shaped position?

Michelson Interferometer With the M1 and M2′ parallel, the fringes are circular and localized at infinity. With M1 and M2′ at a slight angle, the interference fringes are straight lines parallel to the equivalent intersection of the mirrors and localized approximately at the intersection.

How does fringe pattern shift in Michelson interferometer?

The fringe shifts indicate that the light going through the vacuum cell has gained on the light that didn’t (because of its greater speed in vacuum). From the number of fringe shifts N, we can calculate the difference in the index of refraction (∆n) between the two media.

How do you calculate the number of fringes in a Michelson interferometer?

The m = 122 fringes observed compose the difference between the number of wavelengths that fit within the empty chamber (vacuum) and the number of wavelengths that fit within the same chamber when it is gas-filled. The wavelength in the filled chamber is shorter by a factor of n, the index of refraction. N=Lλ=2tλ0/n.

### Why are fringes circular in Michelson interferometer?

Because the aperture of the eye is relatively small you will not see many fringes unless you move your eye. This results in the fringes being circular. When the two mirrors are coincident you will not see a uniform blackness due to imperfections in the mirrors.

### What does the Michelson interferometer do?

A Michelson interferometer is used to measure the wavelength of light put through it. When the movable mirror is moved by exactly 0.100 mm, the number of fringes observed moving through is 316.

What is the Michelson interferometer used for?

The Michelson interferometer and its modifications are used in the optical industry for testing lenses and prisms, for measuring index of refraction, and for examining minute details of surfaces (microtopographies). The instrument consists of a half-silvered mirror that divides a light beam into two equal parts,…

How does the Michelson interferometer work?

The Michelson interferometer produces interference fringes by splitting a beam of light so that one beam strikes a fixed mirror and the other a movable mirror. When the reflected beams are brought back together, an interference pattern results.

#### How do you obtain localized and straight fringes in Michelson interferometer?

Place a Na light source at L and a cross-wire between L and G. View the cross-wire from the position E and adjust the tilting screws behind the mirror M2 so as to superimpose the two images (one from M1 and one from M2). When the two images coincide, interference fringes will be visible.

What are Localised fringes in Michelson interferometer?

The localized fringes are obtained in Michelson interferometer, irrespective of coherence of sources, if the two mirrors are tilted with respect to each other. The fringe formation and localization also depends upon coherence of optical waves, interfering medium, polarization etc.

What is a Michelson interferometer?

The Michelson interferometer (invented by the American physicist Albert A. Michelson, 1852–1931) is a precision instrument that produces interference fringes by splitting a light beam into two parts and then recombining them after they have traveled different optical paths.

## How many fringes are observed when the micrometer clamps down on the foil?

There is a difference of 27 fringes in the observed interference pattern when the micrometer clamps down on the foil compared to when the micrometer is empty. Calculate the thickness of the foil?

## What is the number of fringes observed when moving the mirror?

When the movable mirror is moved by exactly 0.100 mm, the number of fringes observed moving through is 316. What is the wavelength of the light? A 5.08-cm-long rectangular glass chamber is inserted into one arm of a Michelson interferometer using a 633-nm light source.

How do you measure minute displacements in an interferometer?

Consequently, by counting the number of fringes m passing a given point as is moved, an observer can measure minute displacements that are accurate to a fraction of a wavelength, as shown by the relation Precise Distance Measurements by Michelson Interferometer A red laser light of wavelength 630 nm is used in a Michelson interferometer.