Nonlinear polarization transfer and control of two laser beams overlapping in a uniform nonlinear medium.

A scheme for polarization control using two laser beams in a non-linear optical medium is studied using both co- and counter-propagating beam geometries. In particular, we show that under certain conditions it is possible for two laser beams to exchange their polarization states. A model accounting for a more realistic, 2D propagation geometry is presented. The 2D model produces drastically different results (compared to the 1D propagation geometry), creating difficulties for implementing polarization control in a realistic setting. A proposal for overcoming these difficulties by reducing the non-linear optical medium to a thin slab is presented.

Antimatter interferometry for gravity measurements.

We describe a light-pulse atom interferometer that is suitable for any species of atom and even for electrons and protons as well as their antiparticles, in particular, for testing the Einstein equivalence principle with antihydrogen. The design obviates the need for resonant lasers through far-off resonant Bragg beam splitters and makes efficient use of scarce atoms by magnetic confinement and atom recycling. We expect to reach an initial accuracy of better than 1% for the acceleration of the free fall of antihydrogen, which can be improved to the part-per million level.

Multiphase nonlinear electron plasma waves.

We present a method for constructing multiphase excitations in the generally nonintegrable system of warm fluid equations describing plasma oscillations. It is based on autoresonant excitation of nonlinear electron plasma waves by phase locking with small amplitude chirped-frequency ponderomotive drives. We demonstrate the excitation of these multiphase waves by performing fully nonlinear numerical simulations of the fluid equations. We develop a simplified model based on a weakly nonlinear analytical theory by applying Whitham's averaged Lagrangian procedure. The simplified model predictions are in good agreement with the results from the warm fluid simulations. Such autoresonantly excited multiphase waves form coherent quasicrystalline structures, which can potentially be used as plasma photonic or accelerating devices. Finally, we discuss the laser parameters required for the autoresonant excitation of nonlinear waves in a plasma.