pinza pequea

The smallest caliper in the world

When we talk about science and technology, we often forget the microscopic world, but it is there that many of the things happen that make possible the wonders that we enjoy from day to day.

Today we will talk about one of humanity’s most useful tools: tweezers, and a new light-activated micro tweezers, the smallest in the world.

It is an experimental device developed through a collaboration between scientists from the Warsaw University of Poland and the AGH University of Science and Technology based in Krakow.

To create it, two optical fibers were needed that were joined to put one next to the other. Each fiber is 125 microns in diameter, which is about the width of a human hair. In addition, both had a liquid crystal elastomer material deposited on their tips. To understand the size you can see the image above, next to the head of an ant Formica polyctena (photo by UW Physics).

When ultraviolet light passes through the fibers from their ends, the material will polymerize, permanently forming two elongated cone-shaped structures: the clamps. Later, when visible green light passes through those same fibers, the LCE cones absorb their energy. This causes them to bend toward each other, grabbing whatever may be between them.

Aa is how the clamps work: you put one type of light to open them and another type of light (of frequency) to close them, all through the ends of the aforementioned optical fiber.

The research is described in an article recently published in the journal Advanced Materials.