This article shows an all-dielectric metasurface consisting of “H”-shaped silicon disks with tilted splitting gaps, which can detect the temperature and refractive index (RI). By introducing asymmetry parameters that excite the quasi-BIC, there are three distinct Fano resonances with nearly 100% modulation depth, and the maximal quality factor (Q-factor) is over 10⁴. The predominant roles of different electromagnetic excitations in three distinct modes are demonstrated through near-field analysis and multipole decomposition. A numerical analysis of resonance response based on different refractive indices reveals a RI sensitivity of 262 nm/RIU and figure of merit (FOM) of 2183 RIU⁻¹. This sensor can detect temperature fluctuations with a temperature sensitivity of 59.5 pm/k. The proposed metasurface provides a novel method to induce powerful TD resonances and offers possibilities for the design of high-performance sensors.

A novel asymmetric all-dielectric metasurface supporting multiple Fano resonances with high quality-factor through the excitation of quasi-bound states in the continuum is theoretically investigated. It is demonstrated that two resonances in the near-infrared wavelength are excited by the symmetry-protected bound state in the continuum, which can be transformed into the electric dipole and the toroidal dipole quasi-BIC resonance with high quality-factor by breaking the symmetry of metasurface. Moreover, the sensing properties based on different liquid refractive indexes are researched theoretically. The results show that the maximum quality-factor of the Fano resonance peak is 8422, and the sensitivity can reach 402 nm/RIU, with a maximum figure of merit of 2400 RIU⁻¹. This research is believed to further promote the development of optical sensing and nonlinear optics.

Existing metasurfaces for high efficiency optical phase control in transmission mode are all based on dielectric materials. Metallic metasurfaces for optical phase control in transmission mode never achieved efficiency above 40%. In this paper, we theoretically demonstrate that metallic metasurface constructed by thick nanoparticles can realize high efficiency (above 85%) phase control in optical wavelength range. We investigated the resonant properties of thick nanoparticle arrays and found that bulk magnetic resonance can be formed by antiparallel dipole electric resonances on thick nanoparticles’ sidewalls. In addition, lateral Fabry-Perot (FP) resonance can be generated in the cavity constituted by adjacent thick nanoparticles. Both of the two resonances exhibit high transmission with near-zero reflection. What’s more, the lateral FP resonance can be utilized to manipulate transmitted phase with high efficiency by adjusting the length of thick nanoparticles. The method proposed here may induce a series of new metasurfaces based on thick nanoparticles for various applications.

The enhancement of the reliability of the silicon-based III–V quantum well lasers, especially of those on an on-axis Si (001) substrate, is of great importance now a days for the development of Si-based photonic and even optoelectronic integrated circuits and is really quite challenging. As an experimental advancement, mainly by inserting a pair of InAlAs strained layers separately into the upper and lower AlGaAs cladding layers to effectively prevent the formation of the in-plane gliding misfit-dislocations within the boundary planes of the active region, the longest room-temperature and continuous-wave lifetime of the InGaAs/AlGaAs quantum well lasers on an on-axis Si (001) substrate with a cavity length of 1500 µm and a ridge width of 20 µm has been prolonged from a very initial record of ∼90 s to the present length longer than 31 min. While, the highest continuous-wave operation temperature of another one with a cavity length of 1000 µm and a ridge width of 10 µm has been shown as 103 °C with an extracted characteristic temperature of 152.7 K, further enhancement of the device reliability is still expected and would mainly depend on the level of the threading-dislocation-density reduction in the GaAs/Si virtual substrate.

We theoretically demonstrate high efficiency broadband −90° to 90° arbitrary optical rotation realized with meta reflectarray composed of a L-shaped silver antenna array, a silica spacer, and a silver ground plane. Co-polarized and cross-polarized components of reflected wave can be manipulated efficiently by adjusting arm length of the L-shaped antenna, and 0° to 90° arbitrary optical rotation with high degree of linear polarization (DoLP) over a broadband can be achieved readily. The phase of cross-polarized field component can be reversed by turning the L-shaped antennas upside down, and 0° to 90° optical rotation can be turned into 0° to −90° rotation. Reflected phase can be shift by π after a 90° rotation of the L-shaped or Γ-shaped antennas, while optical rotation angle remains the same. Thus, rotation angle θ is changed to 180° + θ after the rotation, and we realized 0° to 360° polarization rotation with a step of 60° with the combination of six discrete structure units. In addition, we proposed metamaterial structures for highly efficient generation of vector beams with these units. The high efficiency broadband arbitrary angle optical rotation will profoundly affect a wide range of applications involving optical polarization.