We study the electro-optic properties of subwavelength-pitch deformed-helix ferroelectric liquid crystals (DHFLC) illuminated with unpolarized light. In the experimental setup based on the Mach-Zehnder interferometer, it was observed that the reference and the sample beams being both unpolarized produce the interference pattern which is insensitive to rotation of in-plane optical axes of the DHFLC cell. We find that the field induced shift of the interference fringes can be described in terms of the electrically dependent Pancharatnam relative phase determined by the averaged phase shift, whereas the visibility of the fringes is solely dictated by the phase retardation.

We developed polymer-dispersed liquid crystals (PDLCs) that effectively scatter light both in the visible and near-infrared ranges simultaneously. Such PDLCs are characterized by an optimal size distribution of nematic liquid crystal droplets within 0.4 − 3 µm, which is achieved due to the specially selected copolymer, the elaborated liquid crystal material as well as the proper cooling mode from the isotropic phase. These PDLC films provide electrically controlled light scattering modulation in the spectral range 300 − 2300 nm with the response time around 10 ms.

In this paper, we report a study on Si nanopatterns, fabricated as a one-dimensional (1D) Si nanograting with a sub-wavelength (≈200 nm) period. Unpolarized light normally incident on the nanopatterned Si becomes partially polarized and chiral over the entire visible range of 380–740 nm. The degree and the state of polarization of light were measured using polarimetric and ellipsometric techniques. The analysis showed that the reflected light is partially linearly polarized and at the same time a slight chirality (Ŝ3≠0) is observed. Although the polarization of the reflected light is related to the 1D nanograting anisotropy, the chiral transformation of the light could be related to a micrometer-scale chiral substructure on the Si nanopatterned surface. This structure results from the dynamic polarization rotation of the femtosecond laser pulses in their filaments in liquid carbon disulfide near the Si surface during the interferential plasmonic self-organization of the surface nanorelief. These results could underline a key enabling process for the fabrication of polarization-sensitive metasurface-based sensors or devices within the common complementary metal-oxide semiconductor (CMOS)-compatible technology.

Laser inscription of form-birefringent nanograting layers inside fused silica by ultrashort (femto-picosecond) laser pulses at 515 nm was studied as a function of laser, average power and pulsewidth in terms of fabrication regimes. Retardance magnitudes were acquired for single birefringent layers inscribed at different laser parameters, enabling fabrication of polarization-based spectral micro-filters in the form of few-layer microdevices and of microfluidic multi-color refractive-index chemo/biosensor.

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