A pulsed laser study of the optogalvanic effect in a neon glow discharge

The optogalvanic effect in a neon glow discharge has been studied. Time-resolved voltage changes in the discharge induced by a 500 ps pulsed dye system were observed. The energy per laser pulse was varied from 20 - 150 μJ. The discharge current was varied from 0.2 - 1.5 mA at neon pressures of 4 and 20 torr. All dipole-allowed 1s²2s²2p⁵3s - 1s²2s²2p⁵3p transitions in the 585 - 700 nm wavelength range were observed. The signals observed were from all four levels ¹P₁, ³P_0,1,2 of the first excited configuration. The largest signals came from the metastable ³P₀ and ³P₂ states demonstrating that they are important in the discharge. Those involving the ¹P₁ state show possible indications of inverted populations. Time-resolved signals from transitions involving the ³P₁ states are presented for the first time. Their shapes may indicate a more dominant role in the ionization process for this ground state coupled state than has previously been suggested.