Exploring the Zeeman Effect: Examining the Effects of Magnetic Fields on Light

[joshd]

So I am doing a practical on the Zeeman effect, and have not been able to find an answer to the following:

The experiment used a cadmium lamp, with it's light going though a fabry-perot interferometer. When the magnetic field was applied perpendicular to the direction of the interferometer, this was observed:

The peak has split into three, because of the splitting of the energy levels, and so photons are produced of three different energies.

When the magnetic field is applied parallel to the interferometer, (there are holes in the magnets for light to shine through), the peak splits up like this:

where the central peak disappears, and only the two side peaks are present.

Why does this happen? I think it's something to do with how the light is polarised, but I don't understand how the different direction in magnetic field can do this?

EDIT: if it's not obvious, each image shows an increase in magnetic field, from 0-~0.6T.

 

[Valerie Park]

When the magnetic field is applied perpendicular to the direction of the interferometer, the splitting is caused by the Zeeman effect. When the magnetic field is applied parallel to the interferometer, the splitting is caused by the Faraday effect. The Zeeman effect is a splitting of energy levels due to the application of a magnetic field, while the Faraday effect is a rotation of the plane of polarization of light in a magnetic field. Thus, when the magnetic field is applied parallel to the interferometer, the plane of polarization is rotated and the peak splits up into two peaks, with the central peak disappearing.

 

[charng]

I can explain the phenomenon you observed in your experiment using the Zeeman effect. The Zeeman effect is a phenomenon where the energy levels of an atom or molecule are split when it is placed in a magnetic field. This splitting occurs because the magnetic field interacts with the electrons in the atom, causing them to change their energy levels.

In your experiment, you observed the splitting of the energy levels of the cadmium atoms in the lamp. When the magnetic field is applied perpendicular to the direction of the interferometer, the energy levels split into three, causing the peak in the spectrum to also split into three. This is because the magnetic field is affecting the electrons in all directions, causing the energy levels to split into three distinct levels.

On the other hand, when the magnetic field is applied parallel to the interferometer, the energy levels split into two, causing the central peak to disappear and leaving only the two side peaks. This is because the magnetic field is now only affecting the electrons in one direction, causing the energy levels to split into two levels.

To understand why the different direction of the magnetic field causes this difference in the splitting of energy levels, we need to consider the orientation of the electron spin. In a magnetic field, the electron spin can either align or oppose the direction of the field. When the field is perpendicular, the electrons can align or oppose the field in three different ways, resulting in three different energy levels. However, when the field is parallel, the electrons can only align or oppose the field in one direction, resulting in only two energy levels.

In summary, the different directions of the magnetic field affect the orientation of the electron spin, which in turn affects the energy levels of the atoms and causes the observed splitting in the spectrum. I hope this explanation helps you understand the Zeeman effect and its effects on light.