A research team led by Boubacar Kanté, Chenming Hu Associate Professor in UC Berkeley's Department of Electrical Engineering and Computer Sciences (EECS) and faculty scientist at the Materials Sciences Division of the Lawrence Berkeley National Laboratory (Berkeley Lab), showed that a semiconductor membrane perforated with evenly spaced and same-sized holes functioned as a perfect scalable laser cavity. They demonstrated that the laser emits a consistent, single wavelength, regardless of the size of the cavity.

The researchers described their invention, dubbed Berkeley Surface Emitting Lasers (BerkSELs), in a study published Wednesday, June 29, in the journal Nature.

"Increasing both size and power of a single-mode laser has been a challenge in optics since the first laser was built in 1960," said Kanté. "Six decades later, we show that it is possible to achieve both these qualities in a laser. I consider this the most important paper my group has published to date."

Despite the vast array of applications ushered in by the invention of the laser—from surgical tools to barcode scanners to precision etching—there has been a persistent limit that researchers in optics have had to contend with. The coherent, single-wavelength directional light that is a defining characteristic of a laser starts to break down as the size of the laser cavity increases. The standard workaround is to use external mechanisms, such as a waveguide, to amplify the beam.