Transient third-order optical nonlinearityχ^(3)of ZnO microcrystallite thin films is measured at various temperatures by using femtosecond degenerate four-wave-mixing.Room-temperature excitonic enhancement of is obse...Transient third-order optical nonlinearityχ^(3)of ZnO microcrystallite thin films is measured at various temperatures by using femtosecond degenerate four-wave-mixing.Room-temperature excitonic enhancement of is observed.The magnitude ofχ^(3)ranges between 10^(-4)to 10^(-6)esu from 4.2K to room temperature.The measuredχ^(3)response time ranging from 200 to 300 fs ultrafast for temperature down to 4.2K.展开更多
We report the femtosecond time-resolved studies of room temperature exciton recombination and ultrafast stimulated emission dynamics in ZnO microcrystallite thin films.A free exciton photoluminescence lifetime of a fe...We report the femtosecond time-resolved studies of room temperature exciton recombination and ultrafast stimulated emission dynamics in ZnO microcrystallite thin films.A free exciton photoluminescence lifetime of a few tens of picoseconds and a decay time of a few picoseconds for the stimulated emission were observed.The relatively slow rise time(3ps)for the P band as the result of exciton-exciton scattering compared with the 0.8ps rise time for the N band attributed to electron-hole plasma recombination clearly distinguished the two stimulated emission processes.展开更多
基金Supported by the National Natural Science Foundation of China under Grants No.69608002the Excellent Young Teacher's Foundation of the Ministry of Education.
文摘Transient third-order optical nonlinearityχ^(3)of ZnO microcrystallite thin films is measured at various temperatures by using femtosecond degenerate four-wave-mixing.Room-temperature excitonic enhancement of is observed.The magnitude ofχ^(3)ranges between 10^(-4)to 10^(-6)esu from 4.2K to room temperature.The measuredχ^(3)response time ranging from 200 to 300 fs ultrafast for temperature down to 4.2K.
基金Supported by the National Natural Science Foundation of China under Grant No.69608002the Excellent Young Teacher's Foundation of the Minis try of Education.
文摘We report the femtosecond time-resolved studies of room temperature exciton recombination and ultrafast stimulated emission dynamics in ZnO microcrystallite thin films.A free exciton photoluminescence lifetime of a few tens of picoseconds and a decay time of a few picoseconds for the stimulated emission were observed.The relatively slow rise time(3ps)for the P band as the result of exciton-exciton scattering compared with the 0.8ps rise time for the N band attributed to electron-hole plasma recombination clearly distinguished the two stimulated emission processes.
