The Brightest Semiconductor Laser Ever: Photonic Crystals Enable Tiny Lasers to Melt Steel

IN 2016, THE JAPANESE GOVERNMENT ANNOUNCED a plan for the emergence of a new kind of society. Human civilization, the proposal explained, had begun with hunter-gatherers, passed through the agrarian and industrial stages, and was fast approaching the end of the information age. As then Prime Minister Shinzo Abe put it, “We are now witnessing the opening of the fifth chapter.” • This chapter, called Society 5.0, would see made-on-demand goods and robot caretakers, taxis, and tractors. Many of the innovations that will enable it, like artificial intelligence, might be obvious. But there is one key technology that is easy to overlook: lasers.