In this study, a perfect metamaterial absorber (PMMA) based on an indium antimonide temperature-sensitive material is designed and investigated in the terahertz region. We demonstrate that it is an ideal perfect narrow-band absorber with polarization-insensitive and wide-angle absorption properties. Numerical simulation results show that the proposed PMMA can be operated as a temperature sensor with a sensitivity of 21.9 GHz/K. A graphene layer was added to the PMMA structure to improve the sensitivity, and the temperature sensitivity was increased to 24.4 GHz/K. Owing to its excellent performance, the proposed PMMA can be applied in thermal sensing, detection, and switching.

We present a technique that utilizes cascaded resonant cylindrical piezoelectric ceramics and multimode optical fibers wound around them to effectively mitigate laser speckle. By precisely driving the ceramics at their resonant frequencies and inducing comprehensive mode scrambling within the multimode fiber, we achieve a remarkable speckle suppression efficiency of up to 94%. To the best of our knowledge, this sets a new benchmark among various methods aimed at suppressing the speckle of a coherent light. Our study thoroughly explores variables influencing efficiency, including the cascading number of piezoelectric ceramics, driving voltage, fiber core diameter, and more. This method has significant promise for diverse applications that require efficient and fast control of speckle contrast.