美国中佛罗里达大学Ayman F. Abouraddy研究组宣布他们进行了光学Broglie–Mackinnon波包的观测。该研究于2023年1月19日发表于国际一流学术期刊《自然—物理学》杂志上。
该团队报道了在异常群速度色散存在的情况下，利用近轴时空耦合脉冲激光场观测光学Broglie–Mackinnon波包。关键是，Broglie–Mackinnon波包的带宽有一个与波包群速度和等效质量相容的上限。与先前观测到的线性传播不变波包在任何轴向平面上的时空轮廓都是x形相比，Broglie–Mackinnon波包的时空轮廓是唯一的o形(相对于空间和时间圆对称)。
通过雕刻它们的时空光谱结构，课题组研究人员在色散介质中产生无色散Broglie–Mackinnon波包，观察它们圆形对称的时空强度分布和封闭轨迹谱，并调整唯一决定波包长度尺度的场参数。
据了解，伴随运动粒子的Broglie波包是色散的，缺乏由粒子质量和速度决定的固有长度尺度。Mackinnon提出了一种由色散Broglie相波构造的局域非色散波包，该色散Broglie相波通过粒子和观察者角色的反转具有固有的长度尺度。到目前为止，Broglie–Mackinnon波包仍停留在理论阶段。
附：英文原文
Title: Observation of optical de Broglie–Mackinnon wave packets
Author: Hall, Layton A., Abouraddy, Ayman F.
Issue&Volume: 2023-01-19
Abstract: de Broglie wave packets accompanying moving particles are dispersive and lack an intrinsic length scale solely dictated by the particle mass and velocity. Mackinnon proposed a localized non-dispersive wave packet constructed out of dispersive de Broglie phase waves that possess an intrinsic length scale via an inversion of the roles of particle and observer. So far, the de Broglie–Mackinnon wave packet has remained a theoretical proposal. Here we report the observation of optical de Broglie–Mackinnon wave packets using paraxial space–time-coupled pulsed laser fields in the presence of anomalous group-velocity dispersion. Crucially, the bandwidth of de Broglie–Mackinnon wave packets has an upper limit that is compatible with the wave-packet group velocity and equivalent mass. In contrast to previously observed linear-propagation-invariant wave packets whose spatio-temporal profiles at any axial plane are X-shaped, those for de Broglie–Mackinnon wave packets are uniquely O-shaped (circularly symmetric with respect to space and time). By sculpting their spatio-temporal spectral structure, we produce dispersion-free de Broglie–Mackinnon wave packets in the dispersive medium, observe their circularly symmetric spatio-temporal intensity profiles and closed-trajectory spectra, and tune the field parameters that uniquely determine the wave-packet length scale.
DOI: 10.1038/s41567-022-01876-6
Source: https://www.nature.com/articles/s41567-022-01876-6