Pump-induced Exceptional Points in Lasers

Institute for Quantum Electronics, ETH-Zu¨rich, CH-8093 Zu¨rich, Switzerland(Dated: April 25, 2012)We demonstrate that the above-threshold behavior of a laser can be strongly affected by excep-tional points which are induced by pumping the laser nonuniformly. At these singularities, theeigenstates of the non-Hermitian operator which describes the lasing modes coalesce. In their vicin-ity, the laser may turn off even when the overall pump power deposited in the system is increased.Such signatures of a pump- induced exceptional point can be experimentally probed with coupledridge or microdisk lasers.