Quantum forces used to automatically assemble tiny device

A tiny gold device for controlling light is built using strange quantum effects hidden in seemingly empty space.

In 1948, physicist Hendrik Casimir theorized that when objects are brought close together in space, some objects experience a very weak gravitational pull due to imperceptible flickering of quantum fields in the gaps between them. Ta. Researchers then confirmed this Casimir effect in the laboratory. Betul Kyucukoz and his colleagues at Sweden’s Chalmers University of Technology have found a way to make this useful.

They wanted to build a cavity that would trap the light using two pieces of gold placed parallel to each other, so that the light would bounce back and forth between them and would not be able to escape. First, we created the bottom edge of the cavity by transferring triangular gold flakes ranging in size from 4 to 10 microns onto a small piece of glass. The top end of the cavity also contained a triangular gold flake, but instead of holding it in place with an instrument, the researchers attached it to the glass in a salt water solution containing an additional triangular gold flake. The gold flakes were then dipped in and then allowed to develop. Instead, work naturally.

One of those forces was the electrostatic force caused by the charge associated with the dissolved salt. Another is the Casimir effect. Kyuchkoz said he observed the experiment under the microscope many times and could always see the Casimir effect in action. This causes the floating gold flakes to move towards the gold flake where one is imprinted on the glass, and then he moves over the imprinted gold flake until the triangular footprints of the two flakes match. It was rotated.

This completes the assembly of a cavity that can trap light. The researchers were able to significantly control the cavity formation process, Kyucukoz says. For example, by using different concentrations of salt, we can adjust the strength of the electrostatic force so that the distance between the flakes is different for each cavity, creating cavities with slightly different dimensions of 100-200 nanometers. It can trap colored light.

Raul Esquivel Sirbento The professor at the National Autonomous University of Mexico said the idea of ​​self-assembly, likened to throwing a Lego set into a pot and a structure emerges without having to manually press the pieces together, is not new. But he said his team’s experiment was more detailed and controlled than previous attempts to exploit the Casimir effect for similar purposes. But the Casimir effect can be very subtle, so there may be other effects here as well that haven’t been detected yet, Esquivel Servent said.

In the future, Küçüköz and his colleagues hope to use the cavity as part of more complex experiments with light, such as placing objects inside the cavity between two gold flakes.