Zeeman Effect Apparatus

Updated, Compact Zeeman Effect Apparatus uses a high resolution Fabry-Perot interferometer and a USB video camera

The Zeeman Effect Apparatus examines the effect of a strong magnetic field on the green emission line of mercury at 545.1 nm. A magnetic field splits the degenerate 7s and 6p electron levels into three and five levels respectively, giving nine allowed transitions. A high resolution Fabry-Perot etalon is used to observe the energy shifts at magnetic field strengths up to 1.0T.

The electromagnet is mounted on a swivel. A slim low pressure mercury discharge lamp fits between the magnet’s pole pieces. A removable steel rod fills a long hole through one pole piece for transverse viewing; the magnet and lamp are swiveled 90° and the rod is replaced by a quarter wave plate for observing circularly polarized light in the longitudinal direction. A separate power supply controls the lamp and magnet.

The optical system contains four elements and an optical bench. A polarizer and a focusing lens are mounted in a common housing. The polarizer can be rotated by 360° for detecting the polarization state of the emitted light. An interference filter with a transmission bandwidth of <10nm selects the mercury emission line at 545.1 nm, and a Fabry-Perot etalon with a resolution (λ/Δλ) of >2 x 106 acts as the resolving element. A USB video camera supplies live observation of the interference fringes.

Video capture and image analysis software is included in the equipment set. The software records the positions and radii of circles drawn over the fringes and calculates the wavelength shift for correlation with the magnetic field strength.
Computer and software requirements: Windows-based computer run-ning Windows 7 or later with at least 64 Mb of RAM and up to 1GB of hard disk space (for storing images)