This work proposes an optically controllable beam-steering device, fabricated using cholesteric liquid crystals (CLCs) that are doped with azobenzene. The trans-cis photoisomerization of azobenzene changes the pitch of the CLC fingerprint structure and shifts the diffraction angle. The diffraction angle increases when the cell is irradiated with UV light, and restored when it is irradiated with green light. Combining the photoisomerization effect with electrical effect, the CLC beam-steering device provides a steering angle of approximately 19 degrees. The tuning is continuous and could be completed within a few seconds.

This work demonstrates a dual-frequency polymer-stabilized liquid crystal pi cell with zero bias and a short response time. The high curing voltage and low curing intensity give the cell a low dark state and a high bright state, such that the transmittance against the applied voltage curve is steep. The response time is under 1ms and is independent of monomer concentration because a strong electric torque is exerted on the liquid crystals. The cell is useful in field-sequential color systems, and the low operating voltage of ∼5V makes the cell compatible with conventional thin film transistor driving voltages.

Recent (HI, x n ) data on rotational Yb and Hf nuclei are used to describe the motivations and techniques for pushing discrete-line spectroscopy to the realm of the weakly populated yrast and non-yrast states. Three aspects of these studies are discussed: extraction of moments of inertia in different aligned bands, observation and understanding of high-frequency band crossings, and dependence of feeding patterns on nuclear structure.