New article: An artificial material controls laser polarization electronically read more at here http://www.spinonews.com/index.php/science/item/3329-an-artificial-material-controls-laser-polarization-electronically

UCLA engineers developed a new technique to control the polarization state of a laser that could lead to a new class of powerful, high-quality lasers for use in medical imaging, chemical sensing and detection.

Polarization is a fundamental property of light that emerges from a laser. The general way to control the polarization of a laser was to use a polarizer or a waveplate. To change its polarization, the polarizer or waveplate must be physically rotated, a slow process that results in a physically larger laser system.

The team developed a specialized artificial material, a type of "metasurface" that can tune laser's polarization state purely electronically, without any moving parts. The material was applied to a class of lasers in the terahertz range of frequencies on the electromagnetic spectrum, which lies between microwaves and infrared waves.

 

[Trapped ions and superconductors face off in quantum benchmark]

 

Benjamin Williams, the principal investigator of the research, said, in our approach, the polarization control is built right into the laser itself. This allows a more compact and integrated setup, as well as the possibility for very fast electronic switching of the polarization. Also, our laser efficiently generates the light into the desired polarization state no laser power is wasted generating light in the wrong polarization.  

Williams said, Terahertz radiation penetrates many materials, such as dielectric coatings, paints, foams, plastics, packaging materials, and more without damaging them.

The work is based on the group's recent development of the world's first vertical-external-cavity surface-emitting laser, or VECSEL, that operates in the terahertz range.

 

The new artificial material covers an area of 2 square millimeters and has a distinct zigzag pattern of wire antennas running across its surface. An electric current run through the wires, selectively energizing particular segments of the laser material, which allows a user to change and customize the polarization state as needed.

More information: [Optica]