Laser absorption spectroscopy with a blue diode laser in an aluminum hollow cathode discharge

A GaN-based blue diode laser is employed for laser absorption spectroscopy in an aluminum hollow cathode glow discharge plasma. A Littrow grating stabilized external resonator is used for tuning the wavelength of laser emission. Scanning the wavelength of the laser probes the absorption profile of aluminum transitions yielding ground state aluminum densities. Hyperfine structure has to be taken into account in order to obtain correct temperatures. The diode laser is used to investigate both the temperature and the density of aluminum atoms sputtered from a cathode surface by ion bombardment from the cathode fall region. The blue diode laser allows quick and easy access to aluminum ground state atoms at low costs. (C) 2002 American Institute of Physics.