The big picture: Printable lasers

Dr Wen-Kai Hsiao of the University of Cambridge Institute for Manufacturing describes an innovation in laser production.

Inkjet technology has been around for more than 50 years and inkjet printers are familiar objects in homes and offices. But the technology has far more potential.

Revolutionary new manufacturing processes are emerging based on inkjet printing, with applications ranging from flat-panel displays, printed circuit boards and photovoltaic cells for power generation. A recent ground breaking idea is to use inkjet technology to ‘print’ lasers.

Laser devices are ubiquitous in modern life; they are used to read data from Blu-ray discs and deliver high-speed internet around the world. They are also common in medical devices and are used for remote sensing in the space industry to name just a few applications.

Today, most lasers are made on silicon wafers using expensive processes similar to those used for microprocessors. However, scientists have developed a way to use inkjet technology to ‘print’ a type of organic laser. The process involves developing lasers based on chiral nematic liquid crystals (LCs), similar to those used in flat-panel LCD displays. Under the right conditions these unique photonic materials can be stimulated to produce laser emissions.

But this process is complex – requiring a cleanroom environment and multiple, intricate production steps. Furthermore, the range of surfaces that can be used is limited – typically glass or silicon.

Researchers at the University of Cambridge have devised a much simpler, customised inkjet process. This involves printing hundreds of small dots of LC materials onto a substrate covered with a wet polymer solution. As this solution dries, the chemical interaction and mechanical stress cause the LC molecules to align, turning the printed dots into individual lasers.

We believe that this simple process can form lasers on virtually any surface, rigid or flexible. The process has been developed to produce compact, tuneable laser sources and high-resolution laser displays. However, by being able to put lasers virtually anywhere, the potential applications are limited only by imagination.

Dr Wen-Kai Hsiao is Research Associate at the University of Cambridge Inkjet Research Centre. The research into printable lasers, undertaken with Dr Damian Gardiner of the Centre for Molecular Materials for Photonics and Electronics, is reported in the journal Soft Matter – scan the QR code to read: