Objective lens and stray light of the laser lithography system; Copyright: Gillian Kiliani

Laser lithography with the Photonic Professional Nanoscribe can be employed to write 3D patterns into photo resists. The principle is based on two photon absorption of a red laser at 780 nm. Light intensity for two photon absorption, however, is only strong enough in the focal spot of the objective lens, resulting in exposure only there. Light can pass the material without exposure everywhere else.

Piezoelectric elements are used to move the sample through the focal spot within a vertical as well as horizontal range of 3 µm. Larger displacements can be achieved by manual adjustment.

The feature size for 2D lithography is 120 nm, in 3D lithography smallest structures of 150 nm are possible.