Photonic properties of heliconical liquid crystals.

Periodic birefringence is today extensively explored as an interesting route for controlling the flow of light. Distinctly, complex fluids with periodic modulations of birefringence can perform as photonic crystals, with the main examples being cholesteric and blue phases birefringent profiles. Here we demonstrate the characteristics of light propagation in heliconical liquid crystal and demonstrate their tunable optical and photonic properties, specifically as one-dimensional photonic crystals, in the regime of heliconical pitch comparable to the wavelength of light. Using a combination of frequency- and time-domain simulations, we show the existence and properties of the photonic band gap, as determined by the relative handedness of the polarization of light and the heliconical structure. We calculate photonic eigenmodes of the light and find the emergence of electric field component along the propagation axis of light, for both left- and right-handed polarization of light, which in turn results in strongly spatially varying Poynting vector that exhibits circular-like and four-leaf-clover-like patterns. As this variation of the Poynting vector is tunable with various material parameters and external (electric) fields, heliconical birefringence photonic crystals show interesting potential for use in tunable photonic applications, such as complex modulation of light beams.