Self-Assembly of Curved Photonic Heterostructures by the Hanging Drop Method

Area of Science:

• Materials Science
• Photonics
• Nanotechnology

Background:

• Planar fabrication limits the complexity and functionality of photonic devices.
• Curved surfaces offer unique optical properties but are challenging to fabricate with integrated functionalities.

Purpose of the Study:

• To develop a method for fabricating free-standing, millimetric curved photonic heterostructures.
• To explore the optical phenomena arising from the integration of various photonic domains on curved surfaces.
• To establish curvature as a functional degree of freedom in photonic device design.

Main Methods:

• Combining hanging-drop self-assembly with melt infiltration and selective inversion.
• Fabricating integrated infiltrated-opal, inverse-opal, embossed, and white-scattering 2.5D metasurface domains.
• Utilizing geometric constraints of curved assemblies for novel optical effects.

Main Results:

• Successfully fabricated millimetric, free-standing curved photonic heterostructures with heterogeneous domains.
• Observed unique optical phenomena including spectrally selected lateral collimation, geometry-shifted ghost images, and curvature-mediated Bragg extraction.
• Demonstrated coupling of order and disorder in curved assemblies, leading to a distributed-coherence regime.

Conclusions:

• Curvature acts as an active functional degree of freedom, not just a geometric constraint.
• The developed self-assembled photonic heterostructures offer a scalable route to multifunctional 3D metasurfaces.
• This work opens new avenues for light-matter interaction studies and advanced photonic device applications.