Chirality-dependent electromagnetically induced transparency based on a double semi-periodic helix metastructure

Optical rotation and electromagnetically induced transparency in a chiral metamaterial with C4 symmetry

We design and fabricate a double-layered chiral metamaterial with 4-fold rotational symmetry, which simultaneously exhibits optical rotation and electromagnetically induced transparency (EIT) effects. Using analytical equivalent circuit model and Lorentz's coupled oscillator model, we interpret the physical mechanisms and derive material equations. Importantly, we find that magnetic dipole and electric quadrupole play important roles in optical rotation and keeping the symmetry of the material equations. Our work offers a better understanding of optical rotation in chiral metamaterials, and provides a new and simple approach to combine optical rotation and EIT effects into a single metamaterial.

The study on size dependent dipole-dipole interaction in the self-assembly of twisting nanoribbons with circular polarization activation

The mechanism of self-assembling process of inorganic nanoparticle (NPs) is still an open question due to the various and non-additive interactions between NPs. Kotov et al reported that the semiconductor NPs can be self-assembled by external activation such as irradiation. In this paper, the twisted CdTe nanoribbons were successfully assembled with circular polar light activation based on the chiral selective resonance absorption. The effect of NP size on the morphology of assemblies under circular polar light irradiation is discussed by introducing a new mechanism of photooxidation induced dipole moment which decreases with increasing sizes of the NPs because of the change of band offsets at the CdS/CdTe interface. Moreover, we find that the competition between the dipole-dipole interaction and electrostatic repulsion can be modulated by the size of the NPs and the concentration of dispersion, which are the key points to produce the chiral twisted nanoribbons.

Recent Theoretical and Experimental Progress in Circularly Polarized Luminescence of Small Organic Molecules

Small organic molecules (SOMs) with fascinating chiroptical properties have received much attention for their potential applications in photoelectric and biological devices. As an important research tool, circularly polarized luminescence (CPL) provides information about the chiral structures of these molecules in their excited state, and has been an active area of research. With the development of the commercially available CPL instrumentation, currently, more and more research groups have attempted to enhance the CPL parameters (i.e., quantum yield and dissymmetry factor) of the chiral SOMs from all aspects. This review summarizes the latest five years progresses in research on the experimental techniques and theoretical calculations of CPL emitted from SOMs, as well as forecasting its trend of development.