Being motivated by the recent result on the emergence of superlattice properties of the helical nanoribbon in an electric field, we analyze its circular dichroism signal. We theoretically demonstrate that electric-field effect on the helical nanoribbon leads to appearance of new spectral lines in circular dichroism.
Here, we analytically study optical activity of chiral semiconductor gammadions whose chirality arises from the nonuniformity of their thickness. We show that such gammadions distinguish between the two circular polarizations upon the absorption of light, unlike two-dimensional semiconductor nanostructures with planar chirality. Chiral semiconductor gammadions of inverse conical shape are found to exhibit the highest dissymmetry of optical response among the nanostructures of the same size. The results of our theoretical study can be used in future applications of semiconductor gammadions in biomedicine and optoelectronics.
We present here a simple quantum-mechanical model that describes interband optical activity of cubical semiconductor nanocrystals with chiral shape irregularities. Using the developed model, we derive the analytical expression for the rotatory strengths of interband transitions and show that the circular dichroism spectra of the chiral-shape nanocrystal consists only of the electric dipole allowed transitions. Taking into account the splitting of the valence band, one can interpret experimental circular dichroism spectra using just a few fitting parameters. The results of our study may prove useful for various branches of nanophotonics, chiral chemistry, and biomedicine.