发信人: litkidium()
整理人: jeter(2000-07-27 23:13:07), 站内信件
|
Gain-assisted superluminal light propagation
L. J. WANG, A. KUZMICH & A. DOGARIU
NEC Research Institute, 4 Independence Way, Princeton, New Jersey 0854
0, USA
Correspondence and requests for materials should be addressed to L.J.W
. (e-mail: [email protected]).
Einstein's theory of special relativity and the principle of causality
1-4 imply that the speed of any moving object cannot exceed that of li
ght in a vacuum (c). Nevertheless, there exist various proposals5-18 f
or observing faster-than- c propagation of light pulses, using anomalo
us dispersion near an absorption line4, 6-8, nonlinear9 and linear gai
n lines10-18, or tunnelling barriers19. However, in all previous exper
imental demonstrations, the light pulses experienced either very large
absorption7 or severe reshaping9, 19, resulting in controversies over
the interpretation. Here we use gain-assisted linear anomalous disper
sion to demonstrate superluminal light propagation in atomic caesium g
as. The group velocity of a laser pulse in this region exceeds c and c
an even become negative16, 17, while the shape of the pulse is preserv
ed. We measure a group-velocity index of ng = -310(5); in practice, th
is means that a light pulse propagating through the atomic vapour cell
appears at the exit side so much earlier than if it had propagated th
e same distance in a vacuum that the peak of the pulse appears to leav
e the cell before entering it. The observed superluminal light pulse p
ropagation is not at odds with causality, being a direct consequence o
f classical interference between its different frequency components in
an anomalous dispersion region.
When a light pulse of frequency v and bandwidth v enters a dispersive
linear medium of an optical refractive index n( v), the light pulse pr
opagates at the group velocity v g = c/ng, where ng = n(v) + vdn(v)/dv
is the group-velocity index. If the group-velocity index remains cons
tant over the pulse bandwidth v, the light pulse maintains its shape d
uring propagation. In recent experiments involving electromagnetically
induced transparency (EIT)20-22, the group-velocity index was greatly
enhanced using the lossless normal dispersion region between two clos
ely spaced absorption lines
原文链接：
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v406/n
6793/full/406277a0_fs.html
--
※ 来源:．月光软件站 http://www.moon-soft.com．[FROM: 202.105.40.75]
发信人: jeter (云胡不归), 信区: Course
标 题: Re: 自然杂志刊登的王利军的文章
发信站: 网易虚拟社区 (Tue Jul 25 21:12:59 2000), 站内信件
这只是三大页论文的前半页，第一作者中文名字准确应为王力军。
另外你提供的URL好象不能直接看到论文，需要登录吧？
【 在 litkidium (,)(,) 的大作中提到: 】
: Gain-assisted superluminal light propagation
:
: L. J. WANG, A. KUZMICH & A. DOGARIU
:
: ......
--
猴哥，师傅被妖怪捉走啦，我们赶紧分行李吧~~~~
※ 来源:．月光软件站 http://www.moon-soft.com．[FROM: 202.104.137.20]
发信人: litkidium (,)(,), 信区: Course
标 题: Re: 自然杂志刊登的王利军的文章
发信站: 网易虚拟社区 (Wed Jul 26 00:47:40 2000), 站内信件
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v406/n
6793/full/406277a0_fs.html
可以直接看到的，看不到可能是因为URL太长自动断开的缘故，
Paste后你检查一下,将第二行的6793/full/406277a0_fs.html 补上
【 在 jeter (云胡不归) 的大作中提到: 】
: 这只是三大页论文的前半页，第一作者中文名字准确应为王力军。
: 另外你提供的URL好象不能直接看到论文，需要登录吧？
:
:
: .......
--
※ 修改:．litkidium 于 Jul 26 00:49:48 修改本文．[FROM: 202.105.40.75]
※ 来源:．月光软件站 http://www.moon-soft.com．[FROM: 202.105.40.75]
|
|