A team of scientists from Cambridge University has found a way to print lasers onto virtually any surface using everyday inkjet technology. The UK-based team hopes that their breakthrough will lead to a wide range of applications, including biomedical testing and laser arrays for displays.
The research was printed in the journal “Soft Matter”, which detailed how the team found a way to ‘print’ an laser onto any surface. Most lasers are made of silicon wafers using expensive processes similar to those used to make microprocessors. However the team from Cambridge’s Centre for Molecular Materials for Photonics and Electronics believed the same effect could be achieved using everyday technologies found in the home.
The team developed lasers based on chiral nematic liquid crystals (LCs), similar to those found in flat-panel LCD displays. They found that under the right conditions, these photonic materials can be stimulated to produce laser emissions. By aligning the helix-shaped structure of the LC molecules properly, the team found that they could act as an optically resonant cavity – which is an essential component of any laser. Once they added a fluorescent dye, the cavity could then be optically excited to produce laser light.
In a press release, the Cambridge team said that “Until now, high quality LC lasers have been produced by filling a thin layer of LC material between two accurately spaced glass plates a hundredth of a millimetre wide. The glass is covered with a specially-prepared polymer coating to align the LC molecules.”
“Unfortunately the process is still a complex one – it requires a cleanroom environment and involves multiple, intricate production steps. Furthermore, the range of substrates available is pretty limited – typically restricted to glass or silicon, for example.”
Working in collaboration with the university’s Inkjet Research Centre, the Cambridge team found a way to align the LC molecules and produce high resolution multi-color laser arrays in one step, by printing them. They used a custom inkjet printing system to print hundreds of small dots of LC materials on to a substrate covered with a wet polymer solution layer. Once the polymer solution dried, the chemical interaction and mechanical stress caused the LC molecules to align and turn the printed dots into individual lasers.
By developing this simple process, the team believe they can form lasers on virtually any surface, rigid or flexible using pre-existing publishing technology. The potential applications are limited only by the imagination.
Images: dmuth and University of Cambridge