Enhancing the optical rotation of chiral molecules using helicity preserving all-dielectric metasurfaces
D. Beutel, P. Scott, M. Wegener C. Rockstuhl, and I. Fernandez-Corbaton
Appl. Phys. Lett. 118, 221108 (2021)
- Date: 2.06.2021
Being able to sense and distinguish the handedness of chiral molecules is crucial for many applications in the life sciences. Here, we explore by theoretical and computational means the ability of achiral and helicity preserving photonic nanostructures to enhance the optical rotation, i.e., the polarization rotation of elliptically polarized light while traversing a solution of chiral molecules. Starting from a helicity preserving isolated dielectric cylinder, we assemble an array thereof, which enhances the optical rotation power by a factor of four, being limited by the inability to enhance the helicity density beyond the near fields attached to the array. To overcome this limitation, we study cavities composed of two arrays of cylinders with the solution of molecules in between. Such cavities enhance the optical rotation power by a factor as large as 270. Our work complements previous research that concentrated on enhancing circular dichroism with similar structures. Measuring and enhancing circular dichroism as well as optical rotation provides more complete information about the molecules under investigation.