We investigate the effect of pump area on lasing modes in an active random medium. Considering the structure characteristics in a real experimental system, the random medium is divided into two regions, i.e. pump and ...We investigate the effect of pump area on lasing modes in an active random medium. Considering the structure characteristics in a real experimental system, the random medium is divided into two regions, i.e. pump and non-pump areas. The dependence of lasing modes on the pump area is qualitatively explained by means of the model in which the lasing is ascribed to the interaction of the complex localized modes in the active random medium with local aperiodic quasi-structure with appropriate pump light. There exist different pump sizes for lasing with different modes. As the pump size decreases in this random system, the pump threshold of the lasing modes increases. There are different lasing modes in different excitation regions in this random system. This gives us some information about the dependence of lasing modes on pump areas in active random media.展开更多
Random fiber lasers(RFLs)have attracted extensive attention due to their rich physical properties and wide applications.Here,a RFL using a cascaded fiber loop mirror(CFLM)is proposed and presented.A CFLM with 10 fiber...Random fiber lasers(RFLs)have attracted extensive attention due to their rich physical properties and wide applications.Here,a RFL using a cascaded fiber loop mirror(CFLM)is proposed and presented.A CFLM with 10 fiber loop mirrors(FLMs)is simulated by the transfer matrix method and used to provide random feedback.Multiple spikes are observed in both the simulated and measured reflection spectra.The RFL operates in a single longitudinal mode near the threshold and a time-varying multilongitudinal mode at higher pump powers.The RFL exhibits a time-varying radio-frequency spectrum.The Lévy–Gaussian distribution transition is observed,as in many RFLs.The operation mechanism of the lasing longitudinal modes and the impact of complex mode competition and mode hopping on the output characteristics are discussed through experimental and theoretical results.In this study,we unveil an artificial random feedback structure and pave another way for the realization of RFLs,which should be a platform for multidisciplinary studies in complex systems.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 60278016 and 10464002.
文摘We investigate the effect of pump area on lasing modes in an active random medium. Considering the structure characteristics in a real experimental system, the random medium is divided into two regions, i.e. pump and non-pump areas. The dependence of lasing modes on the pump area is qualitatively explained by means of the model in which the lasing is ascribed to the interaction of the complex localized modes in the active random medium with local aperiodic quasi-structure with appropriate pump light. There exist different pump sizes for lasing with different modes. As the pump size decreases in this random system, the pump threshold of the lasing modes increases. There are different lasing modes in different excitation regions in this random system. This gives us some information about the dependence of lasing modes on pump areas in active random media.
基金supported by the National Key R&D Program of China(Grant No.2023YFE0105800)the National Natural Science Foundation of China(Grant Nos.62275093 and 61775074)the Key R&D Program of Hubei Province(Grant No.2021BAA036).
文摘Random fiber lasers(RFLs)have attracted extensive attention due to their rich physical properties and wide applications.Here,a RFL using a cascaded fiber loop mirror(CFLM)is proposed and presented.A CFLM with 10 fiber loop mirrors(FLMs)is simulated by the transfer matrix method and used to provide random feedback.Multiple spikes are observed in both the simulated and measured reflection spectra.The RFL operates in a single longitudinal mode near the threshold and a time-varying multilongitudinal mode at higher pump powers.The RFL exhibits a time-varying radio-frequency spectrum.The Lévy–Gaussian distribution transition is observed,as in many RFLs.The operation mechanism of the lasing longitudinal modes and the impact of complex mode competition and mode hopping on the output characteristics are discussed through experimental and theoretical results.In this study,we unveil an artificial random feedback structure and pave another way for the realization of RFLs,which should be a platform for multidisciplinary studies in complex systems.
