Nanostructured In₃SbTe₂ antennas enable switching from sharp dielectric to broad plasmonic resonances

Area of Science:

• Nanophotonics
• Materials Science
• Metamaterials

Background:

• Phase-change materials (PCMs) offer non-volatile optical tuning in nanophotonic components.
• In3SbTe2 (IST) is a plasmonic PCM with a significant permittivity sign change in its crystalline phase.
• Previous studies focused on unpatterned IST films, leaving nanostructured antennas unexplored.

Purpose of the Study:

• Investigate nanostructured In3SbTe2 (IST) rod and disk antennas.
• Demonstrate optical resonance switching using PCMs.
• Explore potential applications in tunable nanophotonic devices.

Main Methods:

• Numerical and experimental investigations of IST rod and disk antennas.
• Microsecond laser pulses for crystallizing IST.
• Characterization of optical resonance properties and switching behavior.

Main Results:

• Switched individual IST antennas from narrow dielectric to broad plasmonic resonances.
• Achieved a 1.2 µm resonance shift in rod antennas, enabling on/off switching with a 2.7 contrast ratio.
• Increased disk antenna resonance width by over 800% (0.24 µm to 1.98 µm) while maintaining resonance wavelength.
• Demonstrated intermediate switching states by controlling crystallization depth.

Conclusions:

• Nanostructured IST antennas enable dynamic control over optical resonances.
• The demonstrated switching capabilities are crucial for developing active spectral filters, tunable absorbers, and switchable flat optics.
• This research paves the way for advanced, reconfigurable nanophotonic devices.