A significant development by UCF researchers to improve laser-beam quality was recently reported in Science magazine.
Lasers are usually used in applications where a precise frequency line is required, such as LIDAR (Light RADAR), fiber telecommunication or data centers. However, lasers often tend to have many conflicting frequency lines that result in low fidelity and lack of performance. This explains that why since the invention of lasers, coming up with a simple yet robust mechanism to limit the number of laser frequency lines without compromising the power has been the goal for laser scientists and engineers.
In the decades since the discovery of the laser there has been the emergence of many tweaks and techniques aimed at reining in unwanted conflicting frequencies. Unfortunately, these methods often severely restrict the laser or are applicable only to very specific configurations.
The newly developed microring laser presented by Mercedeh Khajavikhan’s research group at UCF’s CREOL, The College of Optics and Photonics, introduces a new approach that departs from the past. Instead of externally filtering unwanted spectrum or suppressing them within the laser cavity by means of intricate components, a single frequency can be obtained by simply pairing the laser with an attenuating identical microring laser in what is known as parity-time (PT) symmetric arrangement.
The CREOL researchers’ new paradigm in resonator design enables multi-moded lasers to exhibit stable single-mode operation, while simultaneously boosting their power.
In their Science paper, the researchers suggest that PT-symmetric lasers may serve as building blocks for an entirely new class of integrated photonic devices that could revolutionize optical communications and information processing. Since mode suppression is carried out on the most fundamental level, the design concept can be adapted to manipulate the content of a wide range of lasers.
“Our PT-symmetric microring lasers constitute an important step forward in the quest for miniaturization,” Khajavikhan said.
The work was coauthored by Khajavikhan, Hossein Hodaei, Mohammad-Ali Miri, Matthias Heinrich, and Demetrios N. Christodoulides.