Quantum Cascade Laser Lives on the Edge

Nature 578, 219 (2020)https://ireap.umd.edu/10.1038/d41586-020-00323-x2020Journal ArticleNonlinear and Quantum Photonics

Devices known as quantum cascade lasers produce useful terahertz radiation, but are typically highly sensitive to fabrication defects. This limitation has now been overcome using a property called topological robustness.