Fast fabrication of silver helical metamaterial with single-exposure femtosecond laser photoreduction
Metallic helical metamaterials have become the prominent candidates for circular polarizers and other optical-chiral devices as they exhibit strong circular dichroism at a broad operation bandwidth. However, the rapid fabrication of an intertwined double helix with multiple pitch numbers and excelle...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
De Gruyter
2019-05-01
|
| Series: | Nanophotonics |
| Subjects: | |
| Online Access: | https://doi.org/10.1515/nanoph-2019-0079 |
| Summary: | Metallic helical metamaterials have become the prominent candidates for circular polarizers and other optical-chiral devices as they exhibit strong circular dichroism at a broad operation bandwidth. However, the rapid fabrication of an intertwined double helix with multiple pitch numbers and excellent mechanical strength, electrical conductivity and surface smoothness remains a challenge. We propose and realize the single-exposure femtosecond laser photoreduction of a freestanding, three-dimensional silver double-helix microstructure by the double-helix focal field intensity engineered with a spatial light modulator. At the same time, the photoreduction solution and the laser repetition rate are optimized to further tackle the surface roughness and the thermal flow problems. As a result, the silver double-helix array with the enhanced quality exhibits pronounced optical chirality in a wide wavelength range from 3.5 to 8.5 μm. This technique paves a novel way to easily and rapidly fabricate metallic metamaterials for chiro-optical devices in the mid-infrared regime. |
|---|---|
| ISSN: | 2192-8606 2192-8614 |