Device and Method of Optically Orienting Biaxial Crystals for Sample Preparation
Timothy Thomas1, George R. Rossman2,
Institute of America, 5355 Armada Dr., Carlsbad, California, USA
Division of Geological and Planetary Sciences, California
Institute of Technology, MS 170-25, Pasadena, California, USA
Deliciously Nerdy Labs, 6170 W Lake Mead Blvd #461-1643, Las Vegas, NV 89108
An optical device we
refer to as the "biaxial orientation device" has been developed for
finding the optical plane, acute bisectrix, and obtuse bisectrix in
biaxial crystals by means of optically aligning conoscopically formed
melatopes and measuring the angular coordinates of the melatopes, where
the angular values allow for determination of the optical plane
containing the optical axes using a vector algebra approach.
After determination of the optical plane, the apparatus allows for the
sample to be aligned in the acute bisectrix or obtuse bisectrix
orientations and to be transferred to a simple mechanical component for
subsequent grinding and polishing, while preserving the orientation of
the polished faces relative to the optical plane, acute bisectrix, and
obtuse bisectrix during the grinding and polishing process.
Biaxial crystalline material samples prepared in the manner are
suitable for accurate spectroscopic absorption measurements in the
acute bisectrix and obtuse bisectrix directions as well as
perpendicular to the optical plane.
The orientation device