Newly Discovered Optical Vortex Was Never Noticed Before

>The rotation around an optical vortex does not concern the direction of the oscillating electric field (polarization), but rather its phase [1]. For example, the maximum of the field might initially be located just above the central axis of a light beam, and then a short time later it’s to the right of the axis, then below. This rotating phase gives the light an orbital angular momentum that can cause a charged particle within the beam to rotate.

So no matter or energy is traveling or transmitting faster than light; a property of the system can be observed to change location faster than the speed of light half of the time. Properties of an object can _change_ at a rate faster than light could propagate in a vacuum, as long as they don't carry information.

Imagine you are shining an incredibly powerful flashlight at the dark surface of the moon. You cover the light with your hand, and then uncover it again. An observer could record the edge of the shadow moving faster than light, but this doesn't mean any physical laws have been broken. No information, energy, or mass has moved faster than light.

>We present the first experimental evidence, supported by theory and simulation, of spatiotemporal optical vortices (STOVs).

The experimental setup is diagrammed and explained in part III.A of the paper:

>In order to experimentally confirm the existence of STOVs, we image the spatiospectral phase and intensity profiles of femtosecond laser pulses midflight during their precollapse and postcollapse evolution in air.

Appendix A gives the experimental setup in enough detail for it to be reproduced in a lab with the correct equipment.