Researchers discover a new way to control infrared light

A team of researchers at MIT Lincoln Laboratory, together with Professor JJ Hu and grad students from DMSE, is devising a way to control infrared light by using phase-change materials instead of moving parts.

A fundamental property of phase-change materials is that they can change how fast light travels through them (the refractive index). “There are already ways to modulate light using a refractive index change, but phase-change materials can change almost 1,000 times better,” says Jeffrey Chou, a team member formerly in the laboratory's Advanced Materials and Microsystems Group.

The team successfully controlled infrared light in multiple systems by using a new class of phase-change material containing the elements germanium, antimony, selenium, and tellurium, collectively known as GSST. This material has been tested successfully in a moving lens. They have also demonstrated its use in infrared hyperspectral imaging, which is used to analyze images for hidden objects or information, and in a fast optical shutter that was able to close in nanoseconds. The next steps are to look closely into real-world applications of GSST and understand what those systems need in terms of power, size, switching speed, and optical contrast.