Non-linear Physics in the Soft X-ray Regime

We have recently fabricated normal-incidence mirrors for focusing 10-200angstrom radiation. By using these reflectors to re-image a short (~1ps) burst of x-rays emanating from a laser produced plasma, we can deliver high- intensity x-ray pulses to a target, potentially inducing non-linear phenomena. Several of these effects will be discussed, including two-photon absorption and third-harmonic generation in noble gases, and exciton creation in solids.