Focusing of laser pulses using a plasma channel lens

Summary form only given. A short plasma channel will focus a laser pulse in a manner similar to a conventional solid lens. Such a plasma channel lens will be able to tolerate laser intensities far above the usual damage limits for conventional optics. This offers the possibility of manipulating intense laser pulses when the spot size is tens of microns and placing the focusing or defocusing optics much closer to the target or interaction region. The focusing properties of the plasma channel lens have been analyzed assuming a fundamental Gaussian laser pulse and a parabolic plasma density profile. Analytical models for the focal spot size r/sub f/ and focal length z/sub f/ in the limits of a thin and thick lens have been derived and compared with simulations using the LEM laser propagation code. The analytical models are derived from a general envelope equation for the laser spot size. The agreement between the analytical models and simulation results is generally quite good, particularly for the thick lens model. Several variations of the simple single tens configuration are examined using the simulation code. Multiple lenses may be placed in series to form an optical transport system, so that the requirements for transporting the beam are decoupled from the requirements of the interaction regime.