A streak camera study of superfluorescence at multiple wavelengths from helium atoms excited using free electron laser pulses
A streak camera study of superfluorescence at multiple wavelengths from helium atoms excited using free electron laser pulses
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使用自由电子激光脉冲激发的氦原子在多个波长下的超荧光的条纹相机研究
DOI：
10.1088/0953-4075/48/10/105002
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
E
中科院分区：
文献类型：
--
作者：
Harries;J.R.;Iwayama;H.;Nagasono;M.;Togashi;T.;Yabashi;M.;Kuma;S.;Nakajima;K.;Miyamoto;Y.;Ohae;C.;Sasao;N.;Shigemasa;E
我们报告了在501.6 nm，667.8 nm和728.1 nm的波长（在空气中）的超荧光的观察后，激发氦原子与自由电子激光脉冲在53.7 nm（n= 3激发）和52.2 nm（n= 4激发）的波长。观察到的超荧光脉冲的波长对应于1 s3 p-1 s2 s，1 s3 d-1 s2 p和1 s3 s-1 s2 p跃迁。观察这些过渡的超荧光意味着要么竞争级联衰减，或直接激发非偶极允许的过渡。我们已经研究了使用条纹相机的时间结构的发射脉冲，结果不能用简单的考虑，使用通常的模型为两个级别的超荧光解释。
We report the observation of superfluourescence at wavelengths (in air) of 501.6 nm, 667.8 nm, and 728.1 nm following the excitation of helium atoms with free-electron laser pulses at wavelengths of 53.7 nm (n= 3 excitation) and 52.2 nm (n= 4 excitation). The observed wavelengths of the superfluorescence pulses correspond to 1s3p–1s2s, 1s3d–1s2p, and 1s3s–1s2p transitions. Observation of superfluorescence on these transitions implies either competing cascade decays, or direct excitation of non-dipole allowed transitions. We have studied the time structure of the emitted pulses using a streak camera, and the results cannot be explained by straightforward considerations using the usual model for two-level superfluorescence.