Lasers discovered to block light, creating darkness

Strange optical effect found could change science's concept of darkness.

Scientists at Brookhaven National Laboratory, USA, have just discovered a strange property of laser beams when using it to shine through certain types of materials.

It all started when the researchers used 3D software to create a diagram for a lighting experiment. However, they found that the laser beam in the simulation appeared as a cylinder, and could even block the light by casting a shadow on the plane.

Laser beams can block light, creating darkness under certain conditions (Photo: HPN).

Too surprised by this result, the team decided to conduct a real experiment to demonstrate the "shadowing of laser beams".

In the experiment, they used a blue laser beam (temporarily called beam A) to shine through a transparent ruby ​​block, then create an interference point perpendicular to a second, green laser beam (beam B).

At the intersection of the two beams, a molecular transformation occurs, causing the electrons to "dance" , with their numbers increasing/decreasing constantly. They call these transition electrons.

Two intersecting laser beams create a dark line, appearing on the plane where the laser beam hits. (Photo: HPN).

The team found that the slightly shorter wavelength of the A-ray was almost immediately 'disturbed' by the transition electrons, blocking its path through the transparent material.

At the same time, beam B also becomes a light blocker. The combination of the two beams creates a dark line, appearing on the plane that beam A is directed at.

This dark line meets all the criteria to be classified as a shadow. It is visible to the naked eye, lying on the plane it is projected on. Even when one of the two light sources is moved, this dark line moves with it.

According to the basic theory of light, photons (the objects that make up light) travel until they hit an object that they cannot pass through. This obstruction creates a shadow, or a small dark patch where the light is obstructed.

However, the above experiment with lasers showed an exception, when light can create a shadow whose composition consists only of itself.

The discovery expands our understanding of light-matter interactions, the team says. It also opens up new possibilities for using light in ways we have never thought of before.