Phase masks are the production tool used to write gratings in fibers and waveguides. Ibsen Phase masks incorporate unbeatable, interferometric (holographic) patterning technology into a production friendly Phase mask.
– enabling single-step patterning of 2D gratings on planar wafers
Ibsen introduces 2D Phase masks for one-step generation of 2D square lattice grating patterns on planar wafers.
2D gratings can now be manufactured by the established Phase mask principles by simply exposing the wafer through an Ibsen 2D Phase mask at Bragg angle incidence, similar to the well known NFH Phase mask mode of operation (i.e. Bragg angle illumination).
By single exposure through an Ibsen Phase mask, and subsequent development of the photo-resist, and etching into the wafer, 2D square lattice grating structures as shown below can be written over large areas on a wafer.
Important features of our line of 2D Phase masks are:
The 2D square lattice Phase mask is illuminated at the Bragg angle, similar to the well known 0/-1 order Phase mask principle. The 2D Phase mask diffracts this illumination into multiple orders – the coherent interference pattern between these accurately reproduces the 2D Phase mask periodicity. Our innovative production techniques allow us to manufacture Phase masks with periods down to 200 nm, while the 2D Phase mask principle of operation limits the upper lattice periodicity to 687 nm (with 435 nm illumination).
The Bragg angle is given by the following equation:
For a given illumination wavelength, the fundamentally possible periodicities are given by the following Criteria of Suitability:
, where Λ is the 2D grating periodicity and λ is the illumination wavelength