Optical diagnostic suite for measuring plasma velocity, laser-ablated metal topography and electron density

We report on the capabilities of our diagnostic system to measure plasma properties including longitudinal velocity, topography of an ablation region and transverse electron density. We generate a plasma by ablating a thin metal film on a transparent substrate with a nanosecond millijoule laser pulse. We use a heterodyne-based Photonic Doppler Velocimeter (PDV) system to measure the velocity of the plasma plume. We also use a Shack-Hartmann interferometer (DOTS) to record the topography of the ablated metal. Also, we extended the functionality of DOTS to examine the transverse electron density of plasma channel in air generated by an intense, self-focused laser pulse. We compare the experimental data in the first two cases to hydrodynamic simulations to provide a feedback loop to improve our theoretical models.