Researchers Create Disposable Lasers with an Inkjet Printer

Lasers have found a role in a plethora of applications since their birth over 50 years ago. They can be found in surgical equipment and common CDs, and they can be used for cutting metal parts, reading product codes and making holograms, among many other uses.

Now researchers from France and Hungary have figured out a way to inexpensively print lasers. Their method is considered so easy and efficient that they believe the core of each laser can actually be disposed of after use.

“The low cost and easiness of laser chip fabrication are the most significant aspects of our results,” said Sébastien Sanaur, an associate professor in the Center of Microelectronics in Provence at the Ecole Nationale Supérieure des Mines de Saint-Étienne in France.

Sanaur and his team developed organic lasers, which magnify light using carbon-containing materials. Though they are not as common as inorganic lasers, such as the ones used in laser pointers, DVD players and optical mice, they do offer benefits such as high-yield photonic conversion, easy production, low cost and a wide range of wavelengths.

Until now, inorganic lasers were not a favorable option because they degrade quickly. But now that they can be produced so inexpensively, they could be tossed away once they fail, possibly expanding their usage.

In order to create the ultra-low-cost organic laser, Sanaur and the team turned to a common inkjet printer.

Inkjet printing is inexpensive, squirting small jets of fluid onto an underlying material. While we mostly think of the inkjet printer we use to print out computer documents, these printers have also been modified to print electronic circuits, pharmaceutical drugs and even human cells.

Figure (a) is a schematic of the laser setup. Figure (b) shows actual lasing capsules. (Image Credit: Sanaur, et al/JAP)

“By piezoelectric inkjet printing, you print ‘where you want, when you want,’ without wasting raw materials,” said Sanaur. “The technique doesn’t require masks, can be done at room temperature and can print onto flexible materials.”

After testing a variety of inks, they decided on a commercial ink variety called EMD6415, which they mixed with dyes. The ink was printed in small square shapes onto a quartz slide.

The dyed ink acted as the core of the laser, also referred to as a gain medium, which amplifies light and produces the narrow, single-color laser beam.

A laser also requires mirrors to reflect light back and forth through the gain medium and an energy source, called a pump, to keep the light amplification going.

The researchers refer to this disposable part of the laser as the “lasing capsule,” and estimate that it could be produced for just a few cents. They envision that it could be swapped out like a replaceable blade in a razor once it deteriorates.

In the future, and with further development, the team believes that the inexpensive inkjet-printed laser could even send data over short plastic fibers and serve as a tool for analyzing chemical or biological samples.