Molecular emissions from laser–solid‐target interactions

摘要

When a high‐power Nd/glass laser pulse is incident on a polyethylene target, a bright plasma plume is created. Subsequently, a cloud of un‐ionized gas is formed which contains 10–100 times the amount of material in the plasma plume. This gas cloud is cold (expansion velocity ∼105 cm/sec) and dense (n≳1019). It is shown to contain diatomic molecules of carbon C2 by heating the core of the cloud with the pulse from a 1‐kJ TEA CO2 laser. Then, the C2 molecules in the cold outer regions of the cloud are seen in absorption on the light emitted by the hot core.