3D imaging of gems and minerals by multiphoton microscopy

Abstract

Many optical approaches have been used to examine the composition and structure of gemstones, both recently and throughout history. The nonlinear optical behavior of different gemstones has not been investigated, and the higher order terms to the refractive index represent an unused tool for qualifying and examining a stone. We have used a multiphoton microscope to examine the nonlinear optical properties of 36 different gemstones and demonstrate that it is a useful tool for imaging them three-dimensionally up to the millimeter scale below the sample surface. The polarization dependence of second harmonic generation signals was used to examine the crystal orientations inside the minerals.

Exploring natural gems and minerals by multiphoton microscopy

“…We have recently published our work demonstrating that a multiphoton microscope can three-dimensionally image gem and mineral samples with high resolution. 15 Multiphoton microscopes are more traditionally used in the biological sciences, and have been very impactful in high profile studies in identifying diseases without stains. 16,17 Our group has used our multiphoton both for biological and material studies, proving the versatility of the instrument.…”

“…Because this conference is about the beauty of optics and nature, this paper will be more qualitative, and we recommend the reader pursue reading our original publication for a more rigorous introduction to these studies. 15…”