Experimental realization of nonlinear demagnification in plasma-based charged particle optics

We experimentally demonstrate nonlinear demagnification (DM) in plasma-based charged particle optics. The nonlinearity originates from the non-uniform penetration of electric fields through the plasma sheath region, when the object beam size (d P ) is reduced to below the Debye length (λ d ). The strength of nonlinearity depends upon d P and λ d , as confirmed from experimental results and a theoretical model. Nonlinear DM is unique to optics of classical Maxwell-Boltzmann systems and unrealized in conventional liquid metal sources where the Fermi Debye length ≪d P . The realization of plasma sheaths being able to control DM can greatly enhance the performance of charged particle optical systems.