Time-resolved studies of ion desorption from Ca surfaces using double-pulsed laser ablation technique

We have performed double-pulsed laser ablation experiments on Ca samples with an ArF excimer laser. The amount of desorbed monovalent ions was measured using a quadrupole mass spectrometer as a function of the delay between the laser pulses. In the case of 6 ns delay, the total amount of desorbed ions is decreased to approximate to 0.1 times that with no delay. On the basis of this result, it is discussed that the laser ablation of Ca metal is caused by multiphoton photochemical reaction via a lattice/defect-assisted mechanism.