Nanooptics and photonics

Dynamics of optical activity of polymer-stabilized blue phase
Iljin A.1, Tereshchenko O.1, Kikuchi H.2, Okumura Y.2
1 Department of Physics of Crystals, Institute of Physics, NAS of Ukraine. Prospect Nauki, 46, Kyiv 03028 Ukraine. 
E-mail: lgtc@iop.kiev.ua
2 Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka, Japan

Blue phase materials have been attracting much interest since 2002, when Kikuchi et al. reported of a huge expansion of the temperature range of the blue phase existence by several tens of degrees on introduction of a small amount of polymers. In this system, referred to as the “polymer-stabilized blue phase” (PSBPh), molecules retain their dynamics and exhibit a rapid electro-optical response to the in-plane electric field [1]. Being comprised of chiral nano-domains PSBPh reveals quite substantial optical activity, which is changed under the on-axis electric field application due to distortion of their twisted molecular structure.
In this paper electric field influence on optical activity of PSBPh cells is studied with respect to the frequency, ω, and voltage, V, applied. Cell preparation peculiarities are also taken into account. Changes of the transmission, T, due to electric-field-induced rotation of light wave polarization reveal a rate-dependent type of hysteresis with a simple phase lag, φ, between the input and output:

Times characteristic of elastic deformations appearing for voltages below 100 V, are of the order of ms. Further increase of the voltage reveals slow viscous inelastic deformations of nano-domains that saturate at approximately 200 V.
Control of light polarization orientation via the electro-optic modulation of optical activity of PSBPh might be useful for optical wave polarization patterning, creation of complex vectorial field profiles or in multichannel optical information processing systems.

1.	Kikuchi H., Yokota M., Hisakado Y., Yang H., Kajiyama T. Polymer-stabilized liquid crystal blue phases // Nat Mater. -2002.-1.-P. 64-68.