| 查看: 391 | 回复: 2 | |||
| 当前主题已经存档。 | |||
| 【有奖交流】积极回复本帖子，参与交流，就有机会分得作者 XXQ_carol 的 10 个金币 | |||
[交流]
【求助】参量下转化是怎么回事儿？
|
|||
|
光在一些晶体中出现参量下转化这种非线性现象，产生纠缠光子对。这个参量下转化到底是怎么回事儿？好像还分了Ⅰ型和Ⅱ型的，这两者有什么区别？ 有没有前辈高人可以指点一下啊！先谢了啊！ [ Last edited by lvzhu2007 on 2008-9-22 at 14:11 ] |
回复此楼» 猜你喜欢
售SCI一区文章，我:8.O.551.O.5.4,科目全,可伽急
已经有7人回复
-
售SCI一区文章，我:8.O.55.1.O.54,科目齐全,可伽急
已经有3人回复
-
明天应该可查了！？
已经有5人回复
-
如果此刻你正在为国基感到焦虑，不妨来听听这首《基金之外》
已经有7人回复
-
没有任何消息-是不是就凉了
已经有8人回复
-
售SCI-T0P文章，我:8O.5.5.1.O.54,科目齐全,可+急
已经有3人回复
-
人气不行了
已经有10人回复
-
我面上完蛋了
已经有10人回复
-
能否退出参与的面上项目解除限项
已经有24人回复
-
filecode，4个jtjc了
已经有17人回复
gaoky2008
木虫 (著名写手)
- 应助: 0 (幼儿园)
- 金币: 6742.6
- 帖子: 1564
- 在线: 139.7小时
- 虫号: 472596
- 注册: 2007-12-04
- 性别: GG
- 专业: 高分子合成化学
|
Wikipedia的解释： Spontaneous parametric down-conversion (SPDC) is an important process in quantum optics. A nonlinear crystal splits incoming photons into pairs of photons of lower energy whose combined energy and momentum are equal to the energy and momentum of the original photon. The state of the crystal is left unchanged in the process, which is why energy and momentum must be conserved (this is related to phase matching in nonlinear optics). This phase matching dictates that the photon pair be entangled in the frequency domain. SPDC is stimulated by random vacuum fluctuations, as such the photon pairs are created at random times. However, if one of the pair (the "signal"  is detected at any time then we know its partner (the "idler" is present. Either signal and idler photons share the same polarisation (type I) or they have perpendicular polarisations (type II). The output of a type I down converter is a squeezed vacuum, which contains only even photon number terms. The output of the type II down converter is a two-mode squeezed vacuum.SPDC allows for the creation of optical fields containing (to a good approximation) a single photon. As of 2005, this is the predominant mechanism for experimentalists to create single photons (also known as Fock states)[1]. The single photons as well as the photon pairs are often used in quantum information experiments and applications like quantum cryptography and the Bell test experiments. 原文地址： http://en.wikipedia.org/wiki/Spo ... ric_down_conversion |
2楼2008-09-22 21:52:40
3楼2008-09-22 22:16:23
