Wide-viewing-angle color holographic 3D display system with high brightness encoding

Holographic display technology, rooted in the Nobel Prize-winning technology, is considered one of the most promising true 3D display technologies for its capability of reconstructing any wavefront with all the depth cues. An ideal holographic display should feature wide viewing angle, high brightness and color display to provide an immersive viewing experience. However, achieving all these features simultaneously remains a significant challenge.

In a newly published paper in PhotoniX, researchers led by Prof. Qiong-Hua Wang of Beihang University, China, have proposed a color holographic display system with wide viewing angle and high brightness. The proposed system, the core component of which is a customized achromatic liquid crystal grating, realizes a nine-time enlargement of viewing angle with ~65° and a five-time increasement in brightness.

The researchers designed an achromatic liquid crystal grating with different pitches under different driving voltages to diffract the red, green and blue light to the same large angle. The achromatic liquid crystal grating is mainly composed of three layers of pixel and common electrodes and two liquid crystal layers. When driving voltages are applied to different layers of pixel electrodes in time sequence, the achromatic liquid crystal grating forms different liquid crystal molecule distributions, which modulate the sequentially incident red, green, and blue light accordingly.

Additionally, a high-brightness hologram encoding method is developed, which utilizes a composite loss function with frequency loss, real loss and imaginary loss. The proposed hologram encoding method is capable of comprehensively learning features in both the frequency domain and the spatial domain, enhancing energy utilization efficiency while ensuring the quality of the reconstructed images.

The reported system answers the urgent call of realizing color holographic display with wide viewing angle and high brightness for an immersive viewing experience. This advancement holds significant potential for broad-ranging applications, including AR, VR, medical technologies, and so on.