Optics and Photonics Society of Iran

- In this paper, the dynamics of optical breakdown in a transparent dielectric material induced by a nanosecond Nd:YAG laser pulse was investigated experimentally. Optical breakdown plasma was induced in PMMA by a Nd:YAG laser beam (operated at 1064 nm and with ~10 ns pulse duration). A portion of the pump laser beam was separated and propagated perpendicularly through the interaction region. Time resolved transmission of the probe beam was used to study the time evolution of the breakdown plasma. The transmitted signal reduces at a threshold time which depends on the pump laser intensity. These results show that the plasma transmissivity decreases with pump laser intensity.