In₃SbTe₂ as a programmable nanophotonics material platform for the infrared

Area of Science:

• Nanophotonics
• Materials Science
• Infrared Optics

Background:

• Phase-change materials (PCMs) offer tuneable optical properties due to distinct amorphous and crystalline phases.
• Existing nanophotonic device fabrication often involves complex, multi-step processes.
• There is a need for advanced materials enabling direct, on-demand modification of nanophotonic structures.

Purpose of the Study:

• To explore the potential of the next-generation PCM, In₃SbTe₂ (IST), for programmable nanophotonics.
• To demonstrate direct laser writing of nanostructures in IST for infrared applications.
• To showcase tuneable optical properties and device functionalities enabled by IST.

Main Methods:

• Utilized In₃SbTe₂ (IST) thin films, a novel PCM with dielectric-to-metallic optical switching in the infrared.
• Employed pulsed laser switching for direct laser writing lithography to create, modify, and erase nanostructures.
• Fabricated and characterized nanoantennas, mid-infrared absorbers, and demonstrated nanoscale 'soldering' effects.

Main Results:

• Achieved direct laser writing of nanostructures on and below the meta-atom level in IST films.
• Demonstrated large resonance shifts (>4 µm) in nanoantennas and a tuneable mid-infrared absorber with ~90% absorptance.
• Showcased capabilities for screening and nanoscale 'soldering' of metallic nanoantennas within the IST material.

Conclusions:

• In₃SbTe₂ (IST) is a highly promising switchable infrared plasmonic PCM for programmable nanophotonics.
• Direct laser writing lithography on IST enables efficient, multi-step-free fabrication of tuneable nanophotonic devices.
• This technology can advance designs for telecommunications, (bio)sensing, and infrared optics, including detectors, emitters, and reconfigurable holograms.