Laser nanofabrication inside silicon with spatial beam modulation and anisotropic seeding.

Nanofabrication in silicon, arguably the most important material for modern technology, has been limited exclusively to its surface. Existing lithography methods cannot penetrate the wafer surface without altering it, whereas emerging laser-based subsurface or in-chip fabrication remains at greater than 1 μm resolution. In addition, available methods do not allow positioning or modulation with sub-micron precision deep inside the wafer.