Miniature robots build world’s smallest house on optical fibre
Image credit: Femto-ST Institute
A team of French scientists have built a micro-robotics system capable of constructing tiny ‘lab-on-fibre’ structures, including the world’s smallest house.
The concept of ‘lab-on-fibre’ technology refers to the integration of miniaturised devices into an optical fibre, enabling the development of optical systems containing useful devices. Although the benefits of mastering lab-on-fibre technologies are appealing, building such small devices has always been challenging, particularly as robotic actuators do not function at the nanoscale.
Now, a team of researchers based at Femto-ST Institute, France, have demonstrated a system - the μRobotex nanofactory - capable of assembling tiny structures by building a house on an optical fibre. The house, which is the world’s smallest, is too small even for a mite to fit through the front door.
“We decided to build the microhouse on the fibre to show that we are able to realise these microsystem assemblies on top of an optical fibre with high accuracy,” said Dr Jean-Yves Rauch, an author of the study.
The researchers miniaturised sensors and integrated them onto fibre tips, such that they could see and handle components at the nanoscale. The researchers had to work using multiple computers to control the extremely delicate process. The necessary components for nanoassembly were placed in a vacuum chamber. They watched through a microscope, as a highly-focused ion beam was used to ‘cut’ the material, a gas injection system was to ‘stick’ the components in place and then detail was added with a low-power ion beam. The ion gun worked over an area just 300μmx300μm.
“For the first time, we were able to realise patterning and assembly with less than two nanometres of accuracy, which is a very important result for the robotics and optical community,” said Rauch.
Although some steps in the process of building the house are already automated, the researchers are keen to fully automate μRobotex assembly in the future.
Following the creation of the striking miniaturised house, the researchers have been using their system to construct smaller and smaller functionalised structures which can be mounted on optical fibres to detect specific molecules. This lab-on-fibre technology could allow for devices to be inserted into otherwise inaccessible locations on optical fibres as thin as human hair, such as into a blood vessel to detect a blood-borne disease.