All-angle negative refraction and active flat lensing of ultraviolet light

Area of Science:

• Physics
• Materials Science
• Optics

Background:

• Veselago predicted left-handed materials with negative refractive indices for unique light propagation.
• Metamaterials enable artificial left-handed responses, typically resonant and limited in frequency.
• Previous efforts scaled down resonant metamaterials to submicrometre sizes for visible light, sacrificing symmetry and limiting frequency ranges.

Purpose of the Study:

• To experimentally implement a bulk metamaterial with a left-handed response in the ultraviolet (UV) spectrum.
• To achieve an omnidirectional left-handed response and a negative refractive index close to -1.
• To demonstrate Veselago flat lensing and all-optical image modulation using the UV metamaterial.

Main Methods:

• Engineered stacked plasmonic waveguides to create a bulk metamaterial structure.
• Characterized the metamaterial's response to transverse magnetic polarized UV light.
• Designed the structure for a refractive index near -1 over a wide angular range.

Main Results:

• Achieved a bulk metamaterial with an omnidirectional left-handed response to UV light.
• Demonstrated a negative refractive index for the metamaterial.
• Successfully implemented Veselago flat lensing for 2D objects beyond the near field.
• Showcased active, all-optical modulation of the transferred image.

Conclusions:

• The developed bulk metamaterial provides a pathway for UV-based negative refraction and advanced optical functionalities.
• This work overcomes previous limitations in scaling left-handed metamaterials to higher frequencies.
• The demonstration of UV flat lensing and all-optical modulation opens new possibilities in nanophotonics and imaging.