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We report a broadband metal-dielectric dispersive mirror (MDDM) based on Al/SiO 2 /HfO 2 thin films operating in the near-ultraviolet (UV) region. Demonstrating the combined benefits of both the wide reflective bandwidth of aluminum in the UV region and the flexible dispersion control capability of HfO 2 /SiO 2 multilayer films, the MDDM has a wide bandwidth, low total thickness, and precise dispersion compensation ability. We propose an initial design based on a shortwave reflection enhancement structure (SWRES) to prevent shortwave light from obtaining a second time-dispersion compensation in the deep metal layer. The SWRES can effectively suppress group delay dispersion (GDD) oscillations in MDDMs. The designed MDDM with low GDD oscillation, low total thickness, and a wide working band was successfully fabricated and characterized. The MDDM was used to generate 15 fs UV pulses. This study demonstrates that metal-dielectric structures can enhance the performance of UV dispersive mirrors and lays the foundation for a new generation of UV femtosecond laser equipment.

Laser wireless power transmission (LWPT) systems have significant applications in the field of wireless energy transmission, including spacecraft sensor networks, satellite-to-satellite communication, and remote power supply. However, continuous laser exposure increases the temperature of the photovoltaic (PV) cells in the LWPT system, thus decreasing the electrical output performance. This work, which we believe is a new approach, is on the basis of a notch film designed by a combined merit function proposed to maintain the electrical output performance while under 1064-nm continuous laser irradiation. Moreover, the thermal stability of PV cells under laser irradiation was investigated, which revealed the recoverability of the open-circuit voltage (Voc) of the cells at different temperatures, and the thermal damage to cells was a gradual process. This process began with the vaporization of the encapsulation adhesive, followed by a decline in, but still recoverable and functional, electrical performance, and finally, the cell was completely damaged. The thermal stability of the PV cells coated with the notch film increased ten-fold compared to those without it. Furthermore, the correlation between the minimum Voc and maximum temperature of the cells with notch films of different performances was established. These investigations serve as references for further optimization of LWPT.