论Bessel波束超光速现象

Bessel波束具有奇异的特性，例如在传播中不发生衍射，而且实验测量证明其群速比光速c要大。对其超光速运动可以用球面波前在对称轴上的干涉作简单解释。2006年有研究人员指出，不仅通常的实宗量Bessel波，虚宗量修正Bessel波也有群速超光速现象。

Superluminal Behaviors in Bessel- beams Propagation

The Bessel beams have very singular properties. For example, the motion of Bessel beam is a non -diffracting beam, and the experimental measurements showed that Bessel beams have a group velocity greater than the light speed . A simple explanation for the superluminal motion is given by the interference of spherical wave fronts on the symmetry axis. And in 2006 the researchers show that, in contrary to the ordinary Bessel waves of real argument, the group velocities of imaginary argument modified Bessel waves are superluminal.