UMD物理学家发现了由激光制成的“烟圈”

Published: Sunday,September 11,2016 - 05:07 inPhysics & Chemistry

相关图像
(单击放大)

轨道角动量(OAM)漩涡(粉红色环形物体)是围绕中心光束旋转的激光结构,much like water circles around a drain.20世纪90年代以来,物理学家和工程师们就把这种类型的激光漩涡作为一种工具来研究,以帮助改进显微镜和电信技术。
Howard Milchberg
Spatiotemporal optical vortices,或STOVs(瘦,灰色环形物体)是最新描述的三维光结构,非常像烟圈。不像其他的激光漩涡,炉灶是时间动态的,which means that they travel along with the central laser pulse.与其他激光漩涡相比,炉具可以被证明对工程应用更广泛地有用。
Howard Milchberg

Most basic physics textbooks describe laser light in fairly simple terms: a beam travels directly from one point to another and,unless it strikes a mirror or other reflective surface,will continue traveling along an arrow-straight path,由于光的波动性,尺寸逐渐扩大。但是,这些基本的规则在高强度激光的作用下就消失了。Powerful laser beams,在适当的条件下,将自己的镜头和“自我聚焦”变得更紧,更强烈的光束。University of Maryland physicists have discovered that these self-focused laser pulses also generate violent swirls of optical energy that strongly resemble smoke rings.在这些甜甜圈形状的轻型结构中,known as "spatiotemporal optical vortices," the light energy flows through the inside of the ring and then loops back around the outside.

The vortices travel along with the laser pulse at the speed of light and control the energy flow around it.The newly discovered optical structures are described in the September 9,《华尔街日报》2016年版Physical Review X.

The researchers named the laser smoke rings "spatiotemporal optical vortices," or STOVs.光结构无处不在,任何强大的激光都很容易创造出来,在适当的条件下。The team strongly suspects that STOVs could explain decades' worth of anomalous results and unexplained effects in the field of high-intensity laser research.

“激光已经研究了几十年,but it turns out that STOVs were under our noses the whole time," said Howard Milchberg,professor of physics and electrical and computer engineering at UMD and senior author of the research paper,who also has an appointment at the UMD Institute for Research in Electronics and Applied Physics (IREAP).“这是一个强大的,spontaneous feature that's always there.This phenomenon underlies so much that's been done in our field for the past 30-some years."

More conventional spatial optical vortices are well-known from prior research--chief among them "orbital angular momentum" (OAM) vortices,光能在光束传播方向上循环,就像水从洗脸盆中流出时绕着排水沟旋转一样。Because these vortices can influence the shape of the central beam,they have proven useful for advanced applications such as high-resolution microscopy.

"Conventional optical vortices have been studied since the late 1990s as a way to improve telecommunications,microscopy and other applications.These vortices allow you to control what gets illuminated and what doesn't,by creating small structures in the light itself," said the paper's lead author Nihal Jhajj,在IREAP进行研究的物理学研究生。

“我们发现的烟环涡可能比以前已知的光学涡有更广泛的应用,因为它们是时间动态的,也就是说,它们与光束一起移动,而不是保持静止。“这意味着环对于操纵接近光速的粒子可能很有用。”

Jhajj and Milchberg acknowledge that much more work needs to be done to understand STOVs,including their physical and theoretical implications.But they are particularly excited for new opportunities that will arise in basic laser research following their discovery of STOVs.

"All the evidence we've seen suggests that STOVs are universal," Jhajj said."Now that we know what to look for,we think that looking at a high-intensity laser pulse propagating through a medium and not seeing STOVs would be a lot like looking at a river and not seeing eddies and currents."

Eventually,STOVs might have useful real-world applications,like their more conventional counterparts.For example,OAM vortices have been used in the design of more powerful stimulated emission depletion (STED) microscopes.STED microscopes are capable of much higher resolution than traditional confocal microscopes,部分原因在于光学涡流提供的精确照明。

有可能以光速与中心光束一起移动,STOVs could have as-yet unforeseen advantages in technological applications,包括扩展光纤通信线路有效带宽的潜力。

"A STOV is not just a spectator to the laser beam,like an angel's halo," explained Milchberg,noting the ability of STOVs to control the central beam's shape and energy flow."It is more like an electrified angel's halo,with energy shooting back and forth between the halo and the angel's head.我们都很高兴看到这一发现将带我们走向未来。”

Source:University of Maryland

最新科学通讯徳赢手机版

Get the latest and most popular 徳赢手机版science news articles of the week in your Inbox!It's free!

Check out our next project,Biology.Net