A paper by Professors Khajavikhan and Christodoulides published in Science

A paper titled "Parity-time–symmetric microring lasers" by Hossein Hodaei, Mohammad-Ali Miri, Matthias Heinrich, Demetrios N. Christodoulides and Mercedeh Khajavikhan was published in Science.

The ability to control the modes oscillating within a laser resonator is of fundamental importance. In general, the presence of competing modes can be detrimental to beam quality and spectral purity, thus leading to spatial as well as temporal fluctuations in the emitted radiation. We show that by harnessing notions from parity-time (PT) symmetry, stable single longitudinal mode operation can be readily achieved in a system of coupled microring lasers. The selective breaking of PT symmetry can be utilized to systematically enhance the maximum attainable output power in the desired mode. This versatile concept is inherently self-adapting and facilitates mode selectivity over a broad bandwidth without the need for other additional intricate components. Our experimental findings provide the possibility to develop synthetic optical devices and structures with enhanced functionality.

See also article titled "UCF Researchers' New 'Microring' Laser Improves Quality of Beams" in UCF Today.

Posted Tuesday, November 4, 2014