Measuring

Magnetic

Field withLight

Presentationof

Thesisfor the

Masters of Science Degree

by

Andreas Danielsson

The Zeeman EffectField off

No splittingField on

Zeeman triplet

The Zeeman Triplet and Its Polarization

Information Carrier

Orientation of B encoded in the polarizationMagnitude of B encoded in the frequency separation

Polarimeter to analyze the polarization statesInterferometer to analyze the frequency information

MOSS-signal

polarizermodulatingbirefringentcrystal

polarizer

detector

light in

The MOSS

Interferogram for the component

for the two components

Switching between the linear components

Contrast modulation

Interferogram for the two –components separately

Solid line -lower

frequencyDashed line -higher

frequency

Switching between the circular components

Phase modulation

Contrast modulation

I = I0/2(1+s.p)s = (s1, s2, s3)p = (cos sin sin 1, sin 2 cos 1)

Select s1, s2 or s3

by appropriate choiceof p.

Polarimeter

Stokes Vectors

S=.5 (sin2 cos 2sin2 sin 2)

S=.25 (-sin2 cos 2-sin2 sin 2-2cos )

S=.25 (-sin2 cos 2-sin2 sin 2cos )

The Zeeman Spectrometer

Raw Signal for Linear Polarization

field off

field on

Raw Signal for Circular Polarization

= 75o

field on = 105o

field on

Magnet close up

The real thing

All the stuff

Demodulation Algorithm (8f)

f

Frequencyspectra

MOSS carrier

Polarimeter sidebands

Demodulation routine in LabView gives field strength and angles in real time.

Spectrometer B vs Hall probe B

Constant tilt angle as B increases

Measurement of tilt angle