Non-Linear Optical materials (NLO): Crystal quality and orientation determination

Components built from NLO materials have to fulfill high quality standards at the crystal surface and within the bulk material. The orientation of the optical axis, in most cases equal to the crystal c axis, is important for optical applications.

Compared to typical anorganic metals, semiconductors and insulators, the NLO materials have more complicated crystal structures with lower symmetry. The structure creates a highly anisotropic environment for light transmitted through the crystal, and causes their special properties. These crystals are usually cut into small bars with dimensions in the millimeter range to be used as active elements in frequency multipliers and optical parametric oscillators. A surface quality determination on such small crystals can often reveal structural faults and cracks within the crystal.

The large unit cells of these materials are a challenge for the Omega Scan method. We were able to determine Omega Scan parameter for the most important orientations of many NLO materials like LBO, BBO and TeO2. Some special modifications were made to the Omega/Theta design to include NLO capabilities for several different materials.

Tools for Non-Linear Optical materials (NLO): Crystal quality and orientation determination