New type of interference-free hologram

May 31. () –

Chinese researchers have developed a new type of hologram, known as “metaholograms”, Capable of projecting multiple high fidelity images without interference.

This advance, featured in eLight magazine by a team from Huazhong University of Science and Technologypaves the way for next-generation technologies, including virtual/augmented reality (AR/VR) displays, information storage, and image encryption.

Metaholograms offer several advantages over traditional holograms, including wider operating bandwidth, higher image resolution, wider viewing angle, and more compact size. However, a major challenge for metaholograms has been their limited information capacity that only allows a few independent images to be projected.

Existing methods can generally provide a small number of display channels, and often suffer from interchannel interference during image projections.

To overcome this limitation, the new research presents an innovative approach based on the k-space translation design strategy, which allows multiple target images to seamlessly switch between “shown” and “hidden” states. The proposed metahologram employs the geometric phase encoding method and consists of millions of subwavelength scale polysilicon nanopillars, each measuring approximately 100 nm, all identical in size but with rotation angles that vary spatially.

The device also incorporates a flat glass waveguide to transmit incident light and takes advantage of properties such as polarization and angle to change the projection of up to six unique high-fidelity images without crosstalk. Additionally, researchers have created a two-channel full-color metahologram and even an eighteen-channel metahologram using a combination of different multiplexing techniques.

This innovation has the potential to significantly improve AR/VR displays by allowing the projection of more complex and realistic scenes. It is also promising for applications in image encryption, where information is encoded in multiple holographic channels for greater security.

The research is a significant advance in the development of high-performance metaholograms with enormously greater information capacity. This study paves the way for exciting new possibilities in several fields, from advanced displays to information encryption and information storage.