Directional laser-driven ion acceleration from microspheres.

Laser-driven ion acceleration is capable of generating ion beams of MeV energy exhibiting unique attributes such as ultralow emittance. Research is still focusing on fundamental laser-target interactions to control further beam attributes. In this Letter we present the observation of directional ion acceleration of irradiated spherical targets through proton imaging. This feature, together with an earlier observed quasimonoenergetic proton burst makes spherical targets extremely attractive candidates for high quality, high repetition rate sources of laser accelerated particles.