‘Flying Saucer’ Colloidal Quantum Dots Produce Brighter, Better Lasers




But the challenge is that most quantum dot lasers are limited to pulses of light lasting just a few nanoseconds — billionths of a second. The Toronto team overcame this problem by changing the shape of the quantum dots, rather than their size. They were able to create quantum dots with a spherical core and a shell shaped like a flying saucer — a ‘squashed’ spherical shape known as an oblate spheroid.

The mismatch between the shape of the core and the shell introduces a tension that spreads apart the electronic states of the quantum dot, lowering the amount of energy needed to trigger the laser. As reported in today’s paper, the innovation means that the quantum dots are no longer in danger of overheating, so the resulting laser can fire continuously.

http://www.rdmag.com/news/2017/03/flying-sauc...id=content