Nonvolatile Phase-Only Transmissive Spatial Light Modulator with Electrical Addressability of Individual Pixels

Area of Science:

• Metasurfaces
• Nanophotonics
• Optical Engineering

Background:

• Active metasurfaces with tunable nanoscatterers are key for high-performance spatial light modulators (SLMs).
• Phase-change materials (PCMs) offer nonvolatile, low-power optical modulation but current designs lack individual pixel control for SLMs.
• Existing electrically controlled PCM metasurfaces are limited to global amplitude modulation, insufficient for SLM applications.

Purpose of the Study:

• To experimentally demonstrate an individually addressable, transmissive metasurface for phase-only spatial light modulation.
• To utilize the low-loss phase-change material Sb2Se3 for enhanced optical modulation.
• To achieve zero static power consumption in a transmissive phase-only SLM.

Main Methods:

• Fabrication of a transmissive metasurface using Sb2Se3 and doped silicon nanowire heaters for individual pixel control.
• Excitation of a quasi-bound-state-in-the-continuum (BIC) mode within a diatomic metasurface structure.
• Employing guided-mode resonance for enhanced light-Sb2Se3 interaction to achieve a 2π phase shift.

Main Results:

• Demonstrated a global phase-only modulation of ~0.2π, a tenfold enhancement over previous methods.
• Achieved deterministic multilevel switching (ten levels) for individual pixel control.
• Successfully demonstrated tunable far-field beam shaping, confirming SLM functionality.

Conclusions:

• Presented the first zero-static power transmissive phase-only SLMs.
• Enabled by electrically controlled, low-loss PCMs and individually addressable meta-molecules.
• This work paves the way for advanced, power-efficient optical modulation devices.