Faraday Effect Apparatus Model: HO-ED-P-04A is designed for the determination of Verdet’s constant of the liquid sample at 532nm and 650nm laser light.
This experiment is suitable for a senior and graduate laboratory to measure the Verdet constant of several commonly available liquids as functions of two different wavelengths were measured. This experiment helps the student to learn how electric and magnetic fields can influence the optical properties of materials.
Faraday rotation is the rotation of the plane of polarization of light due to magnetic-field-induced circular birefringence in a material. In a nonabsorbing or weakly absorbing medium a linearly polarized monochromatic light beam passing through the material along the direction of the applied magnetic field experiences circular birefringence, which results in rotation of the plane of polarization of the incident light beam.
The materials used in this experiment are SF10, water, Ferric chloride solution, cinnamic acid etc. Cinnamic acid is also known as ethyl cinnamate, has a relatively high index of refraction in the visible, and also exhibits substantial dispersion.
Faraday rotation measurements are taken at two different wavelengths, the green diode laser at 532nm and the red diode laser at 650nm. Laser light transmitted through a column of test liquid contained in a glass tube. The glass tube is coaxial with a solenoid coil. At the entrance end the light is plane polarized by a linear polarizer . At the exit end, the plane of polarization is determined by rotating a second polarizer called the analyzer to obtain extinction of the transmitted light. Precision polarizer rotator mount is used to take the measurement of angular rotation of the polarizer. Measure the angle of rotation for a series of coil currents.
Fill the liquid sample in a glass cell with flat optical ends such that no empty space exists. Now insert the glass cell so that the solenoid hole with the inserted liquid sample is aligned with the optical axis. The corresponding Verdet constant is calculated using the relation
V = θ / (B.L)
Verdet constant is evaluated as a function of the wavelength.
Dual Pass Configuration (Optional)
We can setup this experiment in optical breadboard with
dual pass configuration for more optical rotation
Laser light is made to travel two times through the magneto optical element by using a beam splitter assembly, So that effective Faraday rotation will be twice as compared to the single pass. This helps to detect very small optical rotation.
HO-ED-P-04A Faraday effect electromagnet power supply has provision for direction switching. Rotation of polarization depends on the direction of the applied magnetic field, a current reversing switch on the power supply allows for easy reversal of the magnetic field.