Abstract
We developed a microscopy technique that can measure the local refractive index without sampling the optical phase delay of the electromagnetic radiation. To do this, we designed and experimentally demonstrated a setup with two colocalized Brillouin scattering interactions that couple to a common acoustic phonon axis; in this scenario, the ratio of Brillouin frequency shifts depends on the refractive index, but not on any other mechanical and/or optical properties of the sample. Integrating the spectral measurement within a confocal microscope, the refractive index is mapped at micron-scale three-dimensional resolution. As the refractive index is probed in epidetection and without assumptions on the geometrical dimensions of the sample, this method may prove useful to characterize biological cells and tissues.
- Received 11 August 2018
DOI:https://doi.org/10.1103/PhysRevLett.122.103901
© 2019 American Physical Society
Physics Subject Headings (PhySH)
Viewpoint
A New Angle on Mapping the Refractive Index
Published 11 March 2019
3D maps of a sample’s refractive index—used in some biomedical tests—can be directly derived from angle-dependent measurements of light scattering from the sample.
See more in Physics