Photomechanical materials perform mechanical work in response to illumination. Photoisomerization-based photomechanical materials may operate in different regimes depending on the intensity of the illuminating light. We examine the photoresponse of liquid crystalline azo-acrylate networks and show that a material property, the characteristic intensity of the material, defines the boundaries between different regimes. Asymptotic analysis indicates that whereas at low relative light levels, photostress is proportional to intensity, at high levels, it is proportional to fluence. Model predictions are in good agreement with the experimental results.

Thermal denaturation of hen egg white lysozyme has been investigated by Brillouin light scattering in the temperature range from 297 to 350 K. Anomalies in the temperature dependences of velocity and damping of hypersound and also in the behavior of the intensity of Brillouin components for the lysozyme solution at thermal denaturation have been revealed. These anomalies are attributable to phase transformations of the protein in the high-temperature region. It has been shown that Brillouin light scattering is a suitable tool for studying the structural evolution of proteins.

Cholesteric liquid crystals are frequently produced by the addition of chiral dopants to achiral nematic hosts. We report here the synthesis and performance of chiral dopants obtained from bio-betulin produced by a fermentation process. An important aspect of this work is to point out that the fermentation process used to obtain the starting materials is much easier and cheaper when carried out in large volumes than isolating it from the natural product. The performance of the dopants obtained from bio-betulin is indistinguishable from those obtained from commercially available synthetic betulin.

Increasingly important photomechanical materials produce stress and mechanical work when illuminated. We propose experimentally accessible performance metrics for photostress and photowork, enabling comparison of materials performance. We relate these metrics to material properties, providing a framework for the design and optimization of photomechanical materials.

Azo-containing liquid crystal elastomers are photomechanical materials that can be actuated via illumination. The photomechanical response is a result of the photoisomerization of the azo moiety, which produces bulk stresses in the material. These stresses arise via two distinct and competing mechanisms: order parameter change induced stress and direct contractile stress. We describe thermomechanical and photomechanical experiments aimed at assessing the relative contributions of these. We show that the details of the attachment of azo dyes to the network can greatly influence the photoresponse. We discuss our results and summarize our findings.

Phase-only liquid crystal on silicon (LCoS) spatial light modulators are used in a variety of applications. Despite their wide use, current phase-only LCoS devices are hindered by their single-polarization modulation. We propose a polarization independent LCoS device which uses a polymer quarter-wave plate for polarization conversion. We designed a custom pixel circuit which enables high driving voltage and high pixel grayscale by utilizing an analog driving frame buffer pixel circuit. Our pixel circuit is optimized for small pixel size and the silicon backplanes can be fabricated at a traditional foundry. We demonstrate polarization independent phase modulation through optical beam steering tests for various input polarizations. Our fabricated device lays the foundation for commercial LCoS devices highly suitable for wavelength selective switches, holographic display, wavefront correction, and optical beam shaping.