
Despite its success, integrated photonics has been missing a key component to achieve complete miniaturization: high-performance chip-scale lasers. While some progress has been made on near-infrared lasers, the visible-light lasers that currently feed photonic chips are still benchtop and expensive. Since visible light is essential for a wide range of applications including quantum optics, displays, and bioimaging, there is a need for tunable and narrow-linewidth chip-scale lasers emitting light of different colors.
Researchers at Columbia Engineering’s Lipson Nanophotonics Group have created visible lasers of very pure colors from near-ultraviolet to near-infrared that fit on a fingertip. The colors of the lasers can be precisely tuned and extremely fast — up to 267 petahertz per second, which is critical for applications such as quantum optics. The team is the first to demonstrate chip-scale narrow-linewidth and tunable lasers for colors of light below red — green, cyan, blue, and violet.
These inexpensive lasers also have the smallest footprint and shortest wavelength (404 nm) of any tunable and narrow-linewidth integrated laser emitting visible light. The study, which was first presented at the CLEO 2021 post-deadline session on May 14, 2021, was published online by Nature Photonics.
The importance of lasers emitting wavelengths shorter than red is clear when you consider some important applications. Displays, for example, require red, green, and blue light simultaneously to compose any color. In quantum optics, green, blue, and violet lasers are used for trapping and cooling atoms and ions. In underwater LiDAR, green or blue light is needed to avoid water absorption. However, at wavelengths shorter than red, the coupling and propagation losses of photonic integrated circuits increase significantly, which has prevented the realization of high-performance lasers at these colors.
“What’s exciting about this work is that we’ve used the power of integrated photonics to break the existing paradigm that high-performance visible lasers need to be benchtop and cost tens of thousands of dollars,” said the study’s lead author Mateus Corato Zanarella, a Ph.D student who works with Michal Lipson, Higgins Professor of Electrical Engineering and Professor of Applied Physics.
“Until now, it’s been impossible to shrink and mass-deploy technologies that require tunable and narrow-linewidth visible lasers. A notable example is quantum optics, which demands high-performance lasers of several colors in a single system,” said Zanarella.
“We expect that our findings will enable fully integrated visible light systems for existing and new technologies,” he added.
The researchers, who have filed a provisional patent for their technology, are now exploring how to optically and electrically package the lasers to turn them into standalone units and use them as sources in chip-scale visible light engines, quantum experiments, and optical clocks.
For more information, contact Holly Evarts at