arXiv subjects

Kristiaan Neyts

Publications and source records attributed to Kristiaan Neyts.

3 recordsLinked to original sources

arXiv2026

A conformally-Euclidean Line Element for evaluating color differences

Starting from our previously proposed line element and considering more ``surface color'' datasets, we derive a simplified version which matches experimental datasets equally well and resulted into a conformally-Euclidean line element, which is conceptually much simpler than any existing color difference metrics. The color difference is written as an Euclidean difference multiplied with a simple factor which depends on the luminance only. In a subspace with constant luminance, as considered by MacAdam, this factor becomes constant and the subspace is flat. The same holds for sufficiently large luminances. Based on this LE we derive perceptual coordinates $\left(A,l_{c},s_{c}\right)$ very similar to the CIELab $\left(L^{*},a^{*},b^{*}\right)$.

physics.optics↗

arXiv2023

Polarization patterning in ferroelectric nematic liquids

The recently discovered ferroelectric nematic liquids incorporate to the functional combination of fluidity, processability and anisotropic optical properties of nematic liquids, an astonishing range of physical properties derived from the phase polarity. Among them, the remarkably large values of second order optical susceptibility encourage to exploit these new materials for non-linear photonic applications. Here we show that photopatterning of the alignment layer can be used to structure polarization patterns. To do so, we take advantage of the flexoelectric effect and design splay structures that geometrically define the polarization direction. We demonstrate the creation of periodic polarization structures and the possibility of guiding polarization by embedding splay structures in uniform backgrounds. The demonstrated capabilities of polarization patterning, open a promising new route for the design of ferroelectric nematic based photonic structures and their exploitation.

cond-mat.soft↗

arXiv2018

Nanophotonic Pockels modulators on a silicon nitride platform

Silicon nitride (SiN) is emerging as a competitive platform for CMOS-compatible integrated photonics. However, active devices such as modulators are scarce and still lack in performance. Ideally, such a modulator should have a high bandwidth, good modulation efficiency, low loss, and cover a wide wavelength range. Here, we demonstrate the first electro-optic modulators based on ferroelectric lead zirconate titanate (PZT) films on SiN, in both the O- and the C-band. Bias-free operation, bandwidths beyond 33 GHz and data rates of 40 Gbps are shown, as well as low propagation losses ($α\approx 1$ dB/cm). A $V_πL\approx$ 3.2 Vcm is measured. Simulations indicate that values below 2 Vcm are achievable. This approach offers a much-anticipated route towards high-performance phase modulators on SiN.

physics.app-ph↗