[18p-F202-1~19] 1.1 Interdisciplinary and General Physics

▲ [18p-F202-17] Theoretical study on sub-ns giant pulse laser induced air breakdown

〇(P)Hwan Hong Lim¹, Takunori Taira¹ (1.IMS)

Keywords:laser induced air breakdown, pulse width tunable microchip laser

Laser ignition has been much attracted to various combustion fields because of its advantages: freedom of ignition point, multiple ignition points, wide acceptance of air/fuel ratio and pressure, etc. Giant pulse ceramic microchip laser can boost laser ignition field because of its high peak power, compactness, stability, and low cost. We recently found out an optimum pulse width t of ~600 ps for air breakdown by a minimum energy and the scaling law of air breakdown threshold intensity I_th using a pulse width tunable monolithic Nd:YAG/Cr:YAG ceramic microchip laser. I_th was almost constant for longer pulses than ~600 ps, but had ~t^-2 scaling for the shorter pulses. In presentation, we consider the mechanism of the scaling law theoretically.