New approach shrinks size of terahertz lasers and allows tuning
A PhD student at the University of Twente's MESA+ Institute for Nanotechnology has combined a free electron source and photonic crystals and claims to have created a more flexible terahertz laser which is significantly smaller than currently available devices.
Terahertz lasers have, until now, been restricted to particular wavelengths because the light source is a semiconductor in which electrons can only take on fixed energy states.
Thomas Denis saw the opportunity to use a free electron laser, in which the electrons are not restricted to fixed states, and a photonic crystal to create a coherent beam.
The photonic crystal, which comprises many tiny 'posts', can be created at micro level and its dimensions and shape determine the rough wavelength. The precise wavelength is set by changing the speed of the electrons being fired at it.
While existing terahertz lasers are often large enough to fill a room, Denis' photonic free electron laser is roughly the size of a domestic microwave oven.
