Reflective metagrating polarimeter for single-shot full-Stokes mapping: toward digital histopathology

Histopathology, the study and diagnosis of disease through analysis of tissue samples, is an indispensable part of modern medicine, especially for treating diseases like cancer. However, the practice is time consuming and labor intensive, a circumstance that compels increasing efforts to improve the process and develop new approaches. One of the prospective histopathology techniques involves mapping changes in the polarization state of light being scattered by the tissue, but the conventional implementation relies on bulky polarization optics and is relatively slow. Here, we report the design, fabrication and characterization of a dedicated metasurface polarimeter operating at the wavelength of 640 nm that enables fast parallel (simultaneous) measurements of the Stokes parameters and degree of polarization, with the Stokes parameters determined with ±2% accuracy. To validate its use for digital histopathology we assemble a miniaturized device integrated with the metasurface polarimeter and map polarization state changes in a tissue phantom designed to mimic a biopsy with a cancerous inclusion. The results obtained are compared with those obtained by using a commercial polarimeter, indicating a great potential of metasurface polarimeter based devices and suggesting several possibilities for significant improvement of the current device implementation. We believe that, with these improvements in place, the considered metasurface polarimeter based devices will be ready for practical histopathology applications in clinical environments.