ATOMIC HYPERFINE-STRUCTURE STUDIES USING TEMPERATURE CURRENT TUNING OF DIODE-LASERS - AN UNDERGRADUATE EXPERIMENT

We present a simple and inexpensive experimental arrangement for hyper fine structure studies in atoms using commercially available laser dio des and hollow cathode lamps. The experiment is highly suitable for th e undergraduate laboratory. This technique can be employed to investig ate the hyperfine structure of rare earth and other elements such as T a and Nb which have large nuclear magnetic and or quadrupole moments. In this paper, we report well-resolved hyperfine structure spectra rec orded for holmium employing optogalvanic spectroscopy. We also report Doppler limited hyperfine structure measurements on the ground state o f rubidium using injection current/temperature tuning of the diode las er. This involves a simple experimental arrangement suitable for under graduate laboratories. The hyperfine coupling constants for the level at 31 443.26 cm(-1) in Ho I are reported for the first time. Details o f the data analysis to obtain accurate hyperfine structure coupling co nstants from the observed spectra are presented. A number of commercia lly available diode lasers in the visible and the near infrared region s and simple in-house developed or commercially available low cost cur rent and temperature controllers can be employed for the present studi es. We employ simple cooling/heating or current modulation for tuning the output wavelength of the diode laser. The presently proposed exper imental arrangement can be assembled easily and requires no machine/gl ass shop facilities. (C) 1998 American Association of Physics Teachers .