Here is more information on how they did this in regards to laws of physics:

Rotational wave packets (RWPs) are time-varying states of motion of rotating microscopic objects like molecules, and they change shapes in an ultrafast time scale, typically some parts in a trillion second. More importantly, because RWPs are governed by the fundamental microscopic physical laws, quantum mechanics, they show a wave-like nature, much different from what macroscopic things exhibit. So, RWPs are one of the ideal play grounds for examining the connection between quantum and classical worlds.

In the present study, the RWPs were created by using a pair of ultrafast laser pulses, of which mutual delay and polarization were properly adjusted. In addition, by using a specially designed ion-imaging setup, the team got images of unidirectional RWPs at a viewing angle that the previous 2D imaging studies could not adopt. As a result, the team succeeded in recording a series of images of time-varying molecular angular distribution with high-spatial resolution, which is nothing but a “movie” on the RWPs with a defined sense of rotation. The movie clearly shows the wave-like nature of the RWPs. Multiple running waves get together at some time to give a highly concentrated spatial orientation and split after a while into parts having different angular velocities, while the overall movement keeps rotating in one direction. This propagation of wave packets may well be expected as a pedantic example of a simple quantum system like rotating molecules in free space, for which mutual interaction is essentially inoperative. Nevertheless, it has never been visualized experimentally so far.

This is awesome and congrats to the team for their accomplishment!  The picture in this post is of nitrogen molecules at super fast speeds.  We also included a cool related video below.

thanks to IMS/NINS for the pic