The dark side of the laser

摘要

Laser beams are usually hard to miss, but a new laser is notable for its lack of light. Steven Cundiff at the University of Colorado in Boulder and his colleagues built the device by modifying a standard quantum-dot diode laser. Normally, lasers are amplified using two mirrors that reflect light between them, but Cundiff s group deposited light-absorbing material onto one of the mirrors. The laser still emitted light, but it flickered off at an extremely rapid and predictable rate.