Whispering gallery mode(WGM)optical microcavities,which are capable of light field confinement and manipulation in a relatively small volume,have gained considerable attention from fundamentals in enhanced light-matte...Whispering gallery mode(WGM)optical microcavities,which are capable of light field confinement and manipulation in a relatively small volume,have gained considerable attention from fundamentals in enhanced light-matter interactions to laser applications[1].Undergoing decades of development,the improvement of lasing performance is always a significant issue,including low threshold and high quality(Q)factor[2].Increasing optical gain and reducing the losses are the key aspects towards the realization of a high-quality WGM laser.A perfect cavity structure and a smooth surface are the most crucial determinants to reduce optical losses and enhance light field confined abilities.展开更多
Launching,tracking,and controlling picosecond acoustic(PA)pulses are fundamentally important for the construction of ultrafast hypersonic wave sources,ultrafast manipulation of matter,and spatiotemporal imaging of int...Launching,tracking,and controlling picosecond acoustic(PA)pulses are fundamentally important for the construction of ultrafast hypersonic wave sources,ultrafast manipulation of matter,and spatiotemporal imaging of interfaces.Here,we show that GHz PA pulses can be all-optically generated,detected,and manipulated in a 2D layered MoS_(2)∕glass heterostructure using femtosecond laser pump-probe.Based on an interferometric model,PA pulse signals in glass are successfully decoupled from the coexisting temperature and photocarrier relaxation and coherent acoustic phonon(CAP)oscillation signals of MoS_(2)lattice in both time and frequency domains.Under selective interface excitations,temperature-mediated interfacial phonon scatterings can compress PA pulse widths by about 50%.By increasing the pump fluences,anharmonic CAP oscillations of MoS_(2)lattice are initiated.As a result,the increased interatomic distance at the MoS_(2)∕glass interface that reduces interfacial energy couplings can markedly broaden the PA pulse widths by about 150%.Our results open new avenues to obtain controllable PA pulses in 2D semiconductor/dielectric heterostructures with femtosecond laser pump-probe,which will enable many investigations and applications.展开更多
基金supported by the National Natural Science Foundation of China(62075041,62375049 and 62335003)the Excellent Postdoctoral Program of Jiangsu Province(2023ZB077)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20210593)the Basic Research Program of Jiangsu Province(BK20222007).
文摘Whispering gallery mode(WGM)optical microcavities,which are capable of light field confinement and manipulation in a relatively small volume,have gained considerable attention from fundamentals in enhanced light-matter interactions to laser applications[1].Undergoing decades of development,the improvement of lasing performance is always a significant issue,including low threshold and high quality(Q)factor[2].Increasing optical gain and reducing the losses are the key aspects towards the realization of a high-quality WGM laser.A perfect cavity structure and a smooth surface are the most crucial determinants to reduce optical losses and enhance light field confined abilities.
基金National Key Research and Development Program of China(2017YFA0700503)Natural Science Foundation of Jiangsu Province(BK20190765,BK20222007)+1 种基金National Natural Science Foundation of China(62335003,11734005,61704024,61821002,61875089,61904082,62075041,62175114)Social Development Program Fund of Jiangsu Province(BE2022827)。
文摘Launching,tracking,and controlling picosecond acoustic(PA)pulses are fundamentally important for the construction of ultrafast hypersonic wave sources,ultrafast manipulation of matter,and spatiotemporal imaging of interfaces.Here,we show that GHz PA pulses can be all-optically generated,detected,and manipulated in a 2D layered MoS_(2)∕glass heterostructure using femtosecond laser pump-probe.Based on an interferometric model,PA pulse signals in glass are successfully decoupled from the coexisting temperature and photocarrier relaxation and coherent acoustic phonon(CAP)oscillation signals of MoS_(2)lattice in both time and frequency domains.Under selective interface excitations,temperature-mediated interfacial phonon scatterings can compress PA pulse widths by about 50%.By increasing the pump fluences,anharmonic CAP oscillations of MoS_(2)lattice are initiated.As a result,the increased interatomic distance at the MoS_(2)∕glass interface that reduces interfacial energy couplings can markedly broaden the PA pulse widths by about 150%.Our results open new avenues to obtain controllable PA pulses in 2D semiconductor/dielectric heterostructures with femtosecond laser pump-probe,which will enable many investigations and applications.
