Nonresonant optogalvanic laser-induced signals in prebreakdown gas discharges. II. Time dependence of voltage response instantaneous value

For pt.I see ibid., vol.26, no.3, p.597-604 (1990). The optogalvanic laser-induced signals from gas discharges reflect the changes in excited and ionized particle balance. In prebreakdown stages of low-biased noble gases the lowest metastable levels are the most populated. Using the polynomial expression derived in Part I to describe metastable population change, an analytic solution for the laser-induced voltage across the gas cell is derived form the simple relationship between metastable atom density and such signal values. The solution has the form of a time-varying exponential polynomial series. Zero, positive, and negative degrees of these exponentials indicate three different processes: steady-state and generation and destruction of the metastable population, respectively. Various coefficients and signal peak values are related to discharge and irradiation conditions. This analysis of prebreakdown gas response to incident laser pulses, based on prior experiments, can be used to predict gas time response in various applications such as nonresonant optical detection, switching, spectroscopy, etc