Holmarc’s Faraday Effect Apparatus Model: HO-ED-P-05 is designed for the determination of Verdet’s constant of a material for multiple wavelengths of light. With its new and integrated design, this device is easier to setup and operate so that students can easily understand its principles and theories.
A glass rod (NSF57) with high refractive index is located on a U shaped laminated variable current electromagnet. 50W Halogen lamp is used as light source.5 Filters 404, 450, 505, 546 & 578nm used in filter assembly as narrow band monochromatic light. The sample is placed in a hole drilled pole piece in electromagnet. Sample with electromagnetic unit kept between two linear polarizers and a power meter is used to measure the light intensity as a function of the analyzer angle θ for a full rotation. Faraday Effect is a magneto optic effect in which the plane of linear polarized light is rotated as it passes through a medium that is placed in a magnetic field.
θ = VB l, Where magnetic flux density B = µ0NI
For a given magnetic field and optical path length , Verdet constant will directly corresponds to optical rotation of plane of polarization of light. Verdet constant depends upon the medium its temperature and the frequency of light.
The angle of rotation depends upon the length of the sample, strength of the magnetic field & a proportionality constant called verdet constant.
|Interference filters||:||404, 450, 505, 546, 578nm|
|Source||:||Tungsten Halogen 50W|
|Glass rod specimen||:||Schott NSF57, 30mm length, 10mm diameter|
|Electromagnet input voltage||:||40V DC, 0 - 4A|
|Analyzer precision||:||1 degree / division|
|Power meter||:||Photo diode sensor, 2 - 20mW & µW|
|Variable power supply||:||0 - 4A, 40V DC|
|Gauss meter||:||0 - 2 Tesla range|