Mind-Blowing Discovery: Peacocks Have Lasers In Their Tails - ScienceAlert

A central problem in semiconductor lasers is deceptively simple: how can one increase optical performance without allowing unwanted modes to oscillate? In broad-area semiconductor lasers, increasing the emission area increases the available power, but it also favors many-mode oscillation and degraded beam quality. Photonic-crystal surface-emitting lasers have addressed this problem by engineering optical coupling inside a two-dimensional photonic lattice. In the large-area limit, recent works have shown that single-mode operation can be preserved by controlling Hermitian and non-Hermitian couplings so that higher-order modes experience larger radiation losses than the fundamental mode1. The lesson is broader than the particular device: a good laser is not defined only by the quality factor (Q) of one mode, but by the threshold margin separating that mode from all its competitors. Recently published in Light: Science & Applications, the work of Peng and colleagues, “Robust single-mode laser via merging bound state in the continuum”, brings this principle into the realm of compact bound-state-in-the-continuum lasers2.

Once called a "solution looking for a problem," long before its full potential emerged, the laser has become a powerhouse of modern life. Thanks to sustained support from the U. S. National Science Foundation, researchers have developed lasers that are precise, powerful and versatile, enabling everything from lightning-fast data networks and LASIK to detailed observations of distant galaxies. A laser is a device that generates a narrow, focused beam of light. Unlike ordinary light, which contains many colors and spreads in all directions, laser light is mostly one color, with coherent waves that move together in step. These properties result from stimulated emission, a quantum process in which one photon nudges an excited atom to release an identical photon, triggering a chain reaction that builds a concentrated, coherent beam. A laser's color corresponds to its wavelength and photon energy, determining how it interacts with materials and the tasks it can perform. This ranges from engraving microchips and transmitting data to cutting metal and performing delicate medical procedures. Because of this precision and intensity, lasers have become indispensable to modern life.