  Ultra-intense lasers produce and manipulate plasmas, allowing to locally
generate extremely high static and electromagnetic fields. This Letter presents
a concept of an ultra-intense optical tweezer, where two counter-propagating
circularly polarized intense lasers of different frequencies collide on a
nano-foil. Interfering inside the foil, lasers produce a beat wave, which traps
and moves plasma electrons as a thin sheet with an optically controlled
velocity. The electron displacement creates a plasma micro-capacitor with an
extremely strong electrostatic field, that efficiently generates
narrow-energy-spread ion beams from the multi-species targets, e.g. protons
from the hydrocarbon foils. The proposed ion accelerator concept is explored
theoretically and demonstrated numerically with the multi-dimensional
particle-in-cell simulations.
