A.H. Gevorgyan, A.N. Kocharian, G.A. Vardanyan
California State University. Los Angeles, United States
pp. 174 - 177
Keywords: photonics liquid crystals, photonic density of states, eigen polarizations diffraction transmission, photonic band gap, optical diode
The photonic crystals of artificial and self-organizing structures with spatial periodic changes in dielectric and magnetic properties have attracted considerable interest recently due to unusual physical properties and wide practical applications. The chiral periodic structure in the scale of optical wavelength gives rise to strong and characteristic circular dichroism responses at visible wavelengths. Here we investigate photonic density, circular dichroism and peculiarities of absorption and emission spectra at various eigen polarizations in multilayered one-dimensional chiral soft matter with two layers of cholesteric liquid crystals and an isotropic defect layer inside. The photonic density of states, circular dichroism, absorption and emission dependencies are obtained as a function of the parameters characterizing absorption and gain. The new absorption and gain effects are established to show that the subject system in some circumstances can work as a low threshold laser, a multi-position trigger, a total wide/narrow band absorber, a wide/narrow band filter etc. This work demonstrates the effects of absorption and emission in photonic crystal layers, which offers a novel approach for understanding of tunable soft matter photonic materials. The circular dichroism of an optically active material is described by differential absorption of the left- and right-handed circularly polarized light.