We describe the construction of an inexpensive iodine spectrometer with a homemade iodine vapour
cell and a self-developed wavemeter based on the Pohl interferometer, around the 670 nm wavelength.
This can be easily realized in an undergraduate teaching laboratory to demonstrate the use of a
diode laser interferometer using a Pohl interferometer and measurement of the wavelength using image
processing techniques. A visible alternative to the infrared diode lasers, the 670 nm diode laser
used here gives undergraduate students a chance to perform comprehensive though illustrative atomic
physics experiments including the Zeeman effect, the Hanle effect, and the magneto-optic rotation
effect with a little tweaking in the present spectrometer. The advantage of the spectrometer is its
ease of construction with readily available optics, electronics, evacuation and glass-blowing
facilities, and easy analysis algorithm to evaluate the wavelength. The self-developed algorithm of
raster sca…