We describe a spectroscopy experiment, suitable for upper-division laboratory courses, that investigates saturated absorption spectroscopy and polarization spectroscopy in a neon discharge. Both experiments use nearly identical components, allowing students to explore both techniques in a single apparatus. Furthermore, because the wavelength of the laser is in the visible part of the spectrum (640 nm), the experiment is well-suited for students with limited experience in optical alignment. The labs nicely complement a course in atomic or plasma physics, provide students with the opportunity to gain important technical skills in the area of optics and lasers, and can provide an introduction to radio-frequency electronics.

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We note that an alternate, cost-effective setup is to run the discharge at ∼150 MHz, corresponding to the 2 m amateur radio band and use components specifically designed for the amateur radio community. One can also use a microwave discharge (Ref. 43), using components derived from a commercial microwave oven and a homebuilt microwave cavity.

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