A microhouse's tiled roof shows the ion gun's new ability to focus on a 300-by-300-micrometer area. Credit: FEMTO-ST Institute

Researchers have devised a way to manufacture optical nanotechnologies and create a “microhouse” so small even a mite cannot fit through the door.

A nanorobotics team from the Femto-ST Institute in Besancon in France have assembled a new microbotics system dubbed the μRobotex nanofactory, which can  build microstructures in a large vacuum chamber and fix components onto optical fiber tips with nanometer accuracy.

The microhouse construction was designed to demonstrate how researchers can advance optical sensing technologies when they manipulate ion guns, electron beams and finely controlled robotic piloting.

Lab-on-fiber technologies previously had no robotic actuators for nanoassembly, preventing engineers from building microstructures at the nano-scale. However, the new discovery allows miniaturtized-sensing elements to be installed on fiber tips, so engineers can see and manipulate different components.

Engineers can also insert optical fibers as thin as a strand of human hair into inaccessible locations like jet engines and blood vessels to detect radiation levels or viral molecules.

“For the first time we were able to realize patterning and assembly with less than two nanometers of accuracy, which is a very important result for the robotics and optical community,” Jean-Yves Rauch, an author on the paper, said in a statement.

The researchers combined all the technological components of nanoassembly—a focused ion beam, a gas injection system and a tiny maneuverable robot—in a vacuum chamber and installed a microscope to view the assembly process.

“We decided to build the microhouse on the fiber to show that we are able to realize these microsystem assemblies on top of an optical fiber with high accuracy,” Rauch said.

The researchers used the focused ion beam similar to how scissors are used, to cut or score the silica membrane “paper” of the house. After the walls folded into position, a lower power setting was selected on the ion gun. Then gas injection sputtered a tiled pattern on the roof, showing the accuracy and flexibility of the system.

In this process, the ion gun had to focus on an area only 300 micrometers by 300 micrometers to fire ions onto the fiber tip and silica membrane.

“It's very challenging to pilot the robot with high accuracy at this cross point between the two beams,” Rauch said.

While many of the steps are already automated, the researchers now hope to automate all of the robotic stages of assembly.

Using the μRobotex system, the researchers are constructing functionalized microstructures that can detect specific molecules by attaching their microstructures onto optical fibers.

The nanorobotics team is hoping to push the limits of the technology further still, by constructing smaller structures and fixing these onto carbon nanotubes, only 20 nanometers to 100 nanometers in diameter.

The study was published in the Journal of Vacuum Science & Technology A.