Saved in:
| Main Authors: | , |
|---|---|
| Format: | Preprint |
| Published: |
2026
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2604.00760 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866910093962903552 |
|---|---|
| author | Mantha, Subrahmanyam S. G. Krishnamoorthy, Harish N. S. |
| author_facet | Mantha, Subrahmanyam S. G. Krishnamoorthy, Harish N. S. |
| contents | Reconfigurable metalenses capable of large focal length tuning, fast response times, and high focusing efficiency while maintaining diffraction-limited operation are highly desirable for next-generation adaptive imaging systems. Phase change chalcogenides provide a promising platform for such devices by exploiting the reversible amorphous-to-crystalline transition to achieve non-volatile tuning with relatively fast switching. However, extending these approaches towards the visible spectrum is challenging because of the reduced meta-atom dimensions, stringent phase coverage requirements, intrinsic material absorption and the need to simultaneously preserve focusing efficiency and image quality across multiple material states. Here, we present a dynamically tunable metalens based on $Sb_2$$S_3$ operating at the edge of the visible spectrum. The design framework combines finite element computations with a genetic algorithm-based inverse design approach to achieve robust phase control in both amorphous and crystalline states. The resulting metalens shows diffraction-limited performance with a minimum focal length tunability of $33\%$, focusing efficiencies of approximately $40\%$ and Strehl ratios of $0.80$ and $0.77$ in the amorphous and crystalline states, respectively. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_00760 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Inverse-designed non-volatile phase change varifocal metalens at the edge of the visible spectrum Mantha, Subrahmanyam S. G. Krishnamoorthy, Harish N. S. Optics Reconfigurable metalenses capable of large focal length tuning, fast response times, and high focusing efficiency while maintaining diffraction-limited operation are highly desirable for next-generation adaptive imaging systems. Phase change chalcogenides provide a promising platform for such devices by exploiting the reversible amorphous-to-crystalline transition to achieve non-volatile tuning with relatively fast switching. However, extending these approaches towards the visible spectrum is challenging because of the reduced meta-atom dimensions, stringent phase coverage requirements, intrinsic material absorption and the need to simultaneously preserve focusing efficiency and image quality across multiple material states. Here, we present a dynamically tunable metalens based on $Sb_2$$S_3$ operating at the edge of the visible spectrum. The design framework combines finite element computations with a genetic algorithm-based inverse design approach to achieve robust phase control in both amorphous and crystalline states. The resulting metalens shows diffraction-limited performance with a minimum focal length tunability of $33\%$, focusing efficiencies of approximately $40\%$ and Strehl ratios of $0.80$ and $0.77$ in the amorphous and crystalline states, respectively. |
| title | Inverse-designed non-volatile phase change varifocal metalens at the edge of the visible spectrum |
| topic | Optics |
| url | https://arxiv.org/abs/2604.00760 |