Holmarc's Zeeman Effect Apparatus (Model No : HO-ED-S-04A) is designed for the determination of e/m ratio, which requires knowledge in optics, mechanics, electromagnetism, modern physics and mathematics. Traditional Zeeman effect apparatus needs more skills in operation and measurement. With it’s new and integrated design, this device is easier to setup and operate so that students can lay focus on understanding the principles and theories involved.
A low-pressure mercury lamp is placed inside a variable current electromagnet. Light passes through a narrow-band interference filter (or Dye based filter), centered around the desired wavelength and enters the Fabry - Perot etalon. This device consists of two reflective parallel plates which serve to transmit strong incoming radiation at different orders of wavelength. Small tilting knobs allow precise and careful adjustments of the plate.
The significant difference in our setup is in the imaging system used for viewing and recording the interference patterns. We use USB 2.0 camera, which can be directly connected to the PC to monitor the fringe pattern and save desired pictures. This makes the alignment of the optics much easier and eliminates the need for photographic processing. The Fabry-Perot etalon is the heart of the apparatus which allows us to detect small shifts in wavelengths of light emitted from the source. Basically, it is a pair of parallel, highly reflective mirrors separated by a distance.
The normal Zeeman Effect is characterized by a triplet splitting of the spectral line if it is observed transversally. The middle component remains at the position of the original line. The two others are shifted by the same range towards higher and lower wavelengths, respectively
An etalon is an optical interferometer, for finding the spacing of the etalon we measure the radius of the circular fringes using Holmarc’s image analysis software ‘Image J’.
Spacing of the etalon t = nD2λ / χn2
D = Distance between Etalon and the camera
n = is the order of rings
λ = wavelength of the light used
χn = difference in the radius of two consecutive rings
µB = hc ( ( Δv ̅ ) / 2 ) / B
( Δv ̅ ) / 2 is the difference in wave numbers of one of the σ-lines with respect to the central lines
h = Planck’s constant
c = Speed of light
B = Magnetic flux density
Planck’s constant, h = ( µB / c ) . 2B / ( Δv ̅ )
Speed of light, c = ( µB / h ) . 2B / ( Δv ̅ )
A gauss meter is used for the calibration of magnetic field. Introduce the gauss meter probe between the poles of electromagnet. Vary the current from zero up to its maximum value and note the corresponding field strength from gauss meter at different intervals.