Doping liquid crystals with nanoparticles is a widely accepted method to enhance liquid crystal’s intrinsic properties. In this study, a quick and reliable method to characterise such colloidal suspensions using an optical multi-parameter analyser, a cross-polarised intensity measurement-based device, is presented. Suspensions characterised in this work are either plasmonic (azo-thiol gold AzoGNPs) or ferroelectric Sn₂P₂S₆ (SPS) nanoparticles in nematic liquid crystals. The elastic constants and rotational viscosity showed nonlinear dependence on the concentration of AzoGNPs, initially increasing at lower concentrations and then decreasing at higher concentrations, indicating some degree of particle aggregation. For the SPS suspension, the elastic constant decreased with doping, while the rotational viscosity increased, in agreement with previous findings. Through viscosity measurements, the stability of SPS suspension over ten years is also highlighted.

Liquid crystal photovoltaic spatial-light modulators use photovoltaic layers as an integrated power source to switch from a transparent to an opaque state depending on the ambient illumination. We use non-invasive cross-polarised intensity measurements, to fit photovoltaic parameters, namely photo-generated voltage and photoconductivity, in a sealed device and map their variation across its surface. This methodology was used to estimate the effect of light intensity on these devices and to monitor changes of the photovoltaic parameters over a nine-month period.