Stark-broadened emission profiles of the Balmer series H<sub>β</sub> lines are measured subsequent to nanosecond laser-induced optical breakdown in gaseous hydrogen. Electron number densities are found from time-resolved spectra from H<sub>β</sub> emissions to be in the range 10<sup>15</sup>–10<sup>18</sup> cm<sup>−3</sup>. These results are compared with H<sub>α</sub> measurements for which number densities as high as 10<sup>19</sup> cm<sup>−3</sup> are determined from Stark widths and Stark shifts. Good agreement is reported for number densities inferred from H<sub>α</sub> and H<sub>β</sub> emissions, down to an electron number density 3 × 10<sup>16</sup> cm<sup>−3</sup>, by accurate treatment of ion dynamics in the theory.
© 2003 Optical Society of America
(020.3690) Atomic and molecular physics : Line shapes and shifts
(140.3440) Lasers and laser optics : Laser-induced breakdown
(300.6210) Spectroscopy : Spectroscopy, atomic
(350.5400) Other areas of optics : Plasmas
Christian G. Parigger, David H. Plemmons, and Eugene Oks, "Balmer Series Hβ Measurements in a Laser-Induced Hydrogen Plasma," Appl. Opt. 42, 5992-6000 (2003)