For decades, the semiconductor transistor has been the workhorse of modern electronics, shrinking steadily to pack more computing power into less space. But transistors have now hit a physical limit, and researchers are turning to light as the next frontier. Photonic chips that process light instead of electrical current promise faster speeds and lower energy use, but they require nanoscale light sources that can be precisely controlled, something that has proven difficult to achieve in a small enough package. Now, Emory physicists led by Hayk Harutyunyan have developed a microscopic light source that meets that challenge, with results published in Optica. The device works by taking two photons of the same color and combining them into a single photon of a different color, a process called second harmonic generation, and it does this in a space more than 100 times smaller than the width of a human hair. What makes it especially powerful is that the light output can be dialed up, dialed down, or shut off entirely using nothing more than an electrical voltage, like a dimmer switch for light at the atomic scale. First-authored by PhD student Yuankai Tang, the work represents the first time this kind of electrical tuning has been demonstrated in a device this small, and it opens a path toward faster communications, more sensitive detectors, and ultimately quantum computers that encode and process information using particles of light rather than electrons.
Read the full story on Emory News: https://news.emory.edu/features/2026/05/esc_new_control_nanoscale_light_28-05-2026/index.html
Also see the story on Optica-OPN: https://www.optica-opn.org/home/newsroom/2026/june/electrically_tuning_second-harmonic_generation/