Development of Inkjet-Printable LC Lasers

ORIGINAL: Sci Tech Daily

by Range

September 24, 2012 

Active laser arrays, of arbitrary pattern, were created by inkjet deposition of self-assembled photonic structures in the form of dye-doped chiral nematic liquid crystals.

Most lasers are made up of silicon wafers using expensive processes, similar to the ones used to make microprocessors. Scientists have designed a new way to print a type of organic laser onto any surface, using technology similar to the one found in many homes.

The scientists published their findings in the journal Soft Matter. The process involved developing lasers based on chiral nematic liquid crystals (LCs), similar to the ones used in flat-panel HDTVs. They are part of a unique class of photonic materials that can be stimulated to produce laser emissions under the right conditions.

If the helix-shaped structure of the LC molecules is properly aligned, it can act as an optically resonant cavity, which is an essential component of any laser. After adding fluorescent dye, the cavity can be optically excited to produce laser light.

Creating LC lasers is a complicated process that needs a cleanroom and involves multiple, intricate production steps. The range of substrates available is limited as well, typically restricted to silicon or glass.

The new process involves printing the LC molecules using a custom inkjet printing system. By printing hundreds of small dots of LC material on a substrate covered with a wet polymer layer, the chemical interaction and mechanical stress causes the LC molecules to align and turns the printed dots into individual lasers as the polymer solution dries.

It’s believed that this process can be adapted for use with existing printing equipment. The process can also be used to print fluorescence tag-based laser arrays, used extensively in biology and medicine.

[via University of Cambridge]