Biot-Savart’s Law Experiment

OBJECTIVES

To study the effect of wave plates on polarized light

• Quarter wave plate
• Half wave plate

PRINCIPLE
Waveplates are optical devices that resolve a light wave into two orthogonal linear polarization components by producing a phase shift between them. The transmitted light may have a different type of polarization than the incident beam due to the induced phase difference. Commonly used retarders are quarter-wave plates and half-wave plates. The quarter-wave plate is used to convert a linearly polarized input beam into a circular (or elliptical) polarized beam and vice-versa. Half-wave plate rotates the plane of polarization of linearly polarized light that is input on it by twice the angle between its optical axis and the initial orientation of the linearly polarized light.

OBJECTIVES

• Observe the effect of a magnetic field on the plane of polarization of polarized light as it passes through a dispersive medium.
• Measure the Verdet’s constant of a given dispersive material.

PRINCIPLE
When linearly polarized light passes through an optical medium in a region of the strong magnetic field, the plane of polarization of linearly polarized light rotates by an angle. The angle of rotation of plane-polarized light is proportional to the length of the optical medium and component of the magnetic field in the direction of light. The factor of proportionality is medium-specific and is called Verdet’s constant. And this effect is known as the Faraday Rotation or Faraday Effect. Discovered by Michael Faraday in 1845, the Faraday effect was the first experimental evidence that light and electromagnetism are related. In the experimental setup, the optical medium is an SF6 glass cube.

Objectives

• To produce and observe the interference pattern.
• To measure the wavelength of laser source using the interferometer.

Principle

Phenomena of interference can be explained by the principle of superposition. Consider two E.M waves simultaneously propagating through the same region of space. The resultant electric field at any point in that region of space is the vector sum of the electric field of each wave. Depending on the strength of the resulting electric field at a point in space where the two waves superpose, we observe dark and bright regions in the interference pattern.

Key Features

• Easy to Setup – The apparatus is built on a sturdy and portable platform. The legs are height adjustable to aid leveling of the platform & precise optical alignment of the laser beam. All this reduces the time taken for setup and aids the ease of measurements.
• High quality beam splitter and reflective mirrors – The setup comes with 40 x 40 x 40mm beam splitter cube and 40 x 40mm (98% highly reflective) mirrors for clear fringe pattern.
• 1 micron step movement – The complex double lever mechanism enables a least count of 1 micron in movement of the fixed mirror. Measurement error is less than 5% in wavelength measurement.