Tiny mirror that controls light in 3D could make microscopes smaller and faster

Researchers at Penn State have developed a tiny mirror capable of controlling light in three dimensions at record speeds. This innovation could potentially shrink and speed up optical systems used in various applications, including brain imaging, augmented reality goggles, and precision manufacturing. The key to this achievement lies in a micro-electromechanical system (MEMS) micromirror, which is a mirror that can move and reshape its reflective surface.

This movement is achieved using aluminum nitride, a piezoelectric material that flexes when a voltage is applied, tilting or reshaping the mirror. The mirror can change its shape to tilt and alter the focal depth of the reflected light, enabling true 3D spatial control of the beam. The mirror is about a millimeter in size, allowing it to respond quickly and change its focus within millionths of a second.

The potential applications of this technology are vast. For neuroscience research, it could enable the development of smaller, mountable miniature microscopes for studying neurobiology in active subjects, as well as lighter glasses and headsets for augmented reality. Additionally, faster scanning could help reduce the exposure time of sensitive samples in biological imaging, minimizing damage or fading.

In augmented reality, the ability of the micromirror to change where light comes into focus could help virtual objects appear at different apparent distances, making them feel more natural to the viewer and reducing eye strain. Moreover, in laser micromachining, this technology could help maintain focus on the surface being worked on, even if it rises or falls, ensuring precise cutting or shaping of manufactured parts.