Microlasers hold great promise for the development of photonics and optoelectronics. At present, tunable microcavity lasers, especially regarding in situ dynamic tuning, are still the focus of research. In this study, we combined a 0.7Pb(Mg_1/3Nb_2/3)O₃-0.3PbTiO₃ (PMN-PT) piezoelectric crystal with a Poly [9,9-dioctylfluorenyl-2,7-diyl] (PFO) microring cavity to realize a high-quality, electrically tunable, whispering-gallery-mode (WGM) laser. The dependence of the laser properties on the diameter of the microrings, including the laser spectrum and quality (Q) value, was investigated. It was found that with an increase in microring diameter, the laser emission redshifted, and the Q value increased. In addition, the device effectively achieved a blueshift under an applied electric field, and the wavelength tuning range was 0.71 nm. This work provides a method for in situ dynamic spectral modulation of microcavity lasers, and is expected to provide inspiration for the application of integrated photonics technology.

Multi-wavelength random lasers with switchable modes have advantages in the fields of novel light source and information security. Here, we propose a dual-wavelength phase transition random laser, which can modulate lasing modes arbitrarily assisted by the phase transition hydrogel. Once the phase transition occurs in hydrogel, the scattering properties of light in the random system changes, affecting the optical feedback mechanism and enabling reversible switching of the dual-wavelength random laser mode between incoherent and coherent states. More appealing, random lasing mixed incoherent mode and coherent mode have been obtained for the first time by controlling the local phase transition of the sample. Based on these properties, an information encryption system is constructed by encoding spectral fingerprints at different modes. This work provides an effective way to precisely control the output modes at different wavelengths in the multi-wavelength random laser, further expanding the application of random lasers in multifunctional light sources, color imaging, and information safety.

Gamma shift at large viewing angles is a critical issue in liquid crystal displays, resulting in grayscale distortion and degraded image quality. In this work, a dual-side in-plane switching (DS-IPS) structure with a small initial azimuth angle is proposed to suppress the gamma shift at large viewing angles. Compared with the traditional IPS structure, the proposed DS-IPS structure exhibits more closely distributed V-T curves over various viewing angles. For an electrode width and gap of 2 μm and 4 μm, the maximum gamma shift at a polar angle of 60° decreases from 0.4148 to 0.2922, corresponding to a reduction of 29.6%. Analysis reveals that the dual-side electrodes generate oppositely directed in-plane electric fields near the top and bottom substrates, while the small initial azimuth angle further modifies the spatial LC director distribution. These effects reduce the viewing angle dependence of the optical path difference, thereby suppressing the gamma shift. The proposed method also maintains favorable viewing angle characteristics and exhibits a faster electro-optical response. These results demonstrate that combining dual-side electrodes with small azimuth angle alignment provides an effective approach for suppressing gamma shift at large viewing angles.