Crafting a 1.5  µm pixel pitch spatial light modulator using Ge₂Sb₂Te₅ phase change material [Invited]

Area of Science:

• Optoelectronics
• Materials Science
• Holography

Background:

• Spatial light modulators (SLMs) are essential for holographic displays.
• Current SLM technologies face limitations in pixel pitch and scalability.
• Phase change materials offer unique properties for optical modulation.

Purpose of the Study:

• To develop a high-resolution SLM with a 1.5 µm pixel pitch.
• To investigate the use of germanium-antimony-tellurium (GST) phase change material for SLMs.
• To explore methods for scaling SLMs for large-format holographic displays.

Main Methods:

• Designed a lateral pixel structure with a bottom indium tin oxide layer for uniform pixel modulation.
• Utilized laser irradiation to alter the GST film's phase for hologram fabrication.
• Fabricated an 8Kx2K hologram to test reconstruction before full circuit implementation.
• Investigated physical tiling of SLMs to overcome size limitations.

Main Results:

• Successfully developed key technologies for a 1.5 µm pixel pitch SLM using GST.
• Demonstrated hologram reconstruction using laser-induced phase changes in GST.
• Identified flatness as the critical factor for successful physical tiling of SLMs.

Conclusions:

• The developed GST-based SLM technology enables high-resolution holographic applications.
• Physical tiling is a viable strategy for creating large-scale holographic displays.
• Ensuring flatness in tiled SLM structures is paramount for effective holographic display realization.