Plasmonic metasurfaces,featuring broadband nonlinear optical responses and exceptional light-field manipulation capabilities,facilitate the passive Q-switching and mode-locking operation of a laser resonator as a satu...Plasmonic metasurfaces,featuring broadband nonlinear optical responses and exceptional light-field manipulation capabilities,facilitate the passive Q-switching and mode-locking operation of a laser resonator as a saturable absorber(SA)and thus enable the generation of short-and ultrashort pulses.Here,for the first time,to our knowledge,we successfully fabricate a transmission-type mid-infrared plasmonic metasurface SA composed of gold nanostructures on the fluoride substrate,leveraging localized resonance enhancement.Its nonlinear optical(NLO)properties are characterized by a home-made~2.78μm pulsed Z-scan system,demonstrating a remarkable modulation depth of up to 30%.By integrating the plasmonic metasurface SA into a simple linear-cavity Er:ZBLAN fiber laser,stable Q-switched mode-locking(QML)operation is achieved with a maximum average output power of 224 mW at 2.78μm.The output exhibits a Q-switched envelope of 768 ns containing mode-locking pulses with 51.42 ps duration at the fundamental repetition rate of 24.5 MHz.This work further expands the application of plasmonic metasurface SAs to the mid-IR wavelength region,by utilizing their enhanced NLO responses and tailored spectral characteristics,enabling them as a core component for next-generation mid-IR ultrafast lasers.展开更多
基金National Natural Science Foundation of China(62205213,12304478,62405194)Natural Science Foundation of Hunan Province(2025JJ60405)+3 种基金Natural Science Foundation of Guangdong Province(2023ZDZX3022,2024A1515012152)Fund of University of South China(231RGC011)Science and Technology Planning Project of Shenzhen Municipality(JCYJ20220818100019040,JCYJ20230808105713028)Guangdong Province Key Construction Discipline Scientific Research Capacity Improvement Project(2021ZDJS107)。
文摘Plasmonic metasurfaces,featuring broadband nonlinear optical responses and exceptional light-field manipulation capabilities,facilitate the passive Q-switching and mode-locking operation of a laser resonator as a saturable absorber(SA)and thus enable the generation of short-and ultrashort pulses.Here,for the first time,to our knowledge,we successfully fabricate a transmission-type mid-infrared plasmonic metasurface SA composed of gold nanostructures on the fluoride substrate,leveraging localized resonance enhancement.Its nonlinear optical(NLO)properties are characterized by a home-made~2.78μm pulsed Z-scan system,demonstrating a remarkable modulation depth of up to 30%.By integrating the plasmonic metasurface SA into a simple linear-cavity Er:ZBLAN fiber laser,stable Q-switched mode-locking(QML)operation is achieved with a maximum average output power of 224 mW at 2.78μm.The output exhibits a Q-switched envelope of 768 ns containing mode-locking pulses with 51.42 ps duration at the fundamental repetition rate of 24.5 MHz.This work further expands the application of plasmonic metasurface SAs to the mid-IR wavelength region,by utilizing their enhanced NLO responses and tailored spectral characteristics,enabling them as a core component for next-generation mid-IR ultrafast lasers.
