journal article·2024-12Open access

Nanometric Ge Films for Ultrafast Modulation of THz Waves with Flexible Metasurface

Kemeng Wang, Yogesh Kumar Srivastava, Thomas CaiWei Tan, Rajour Tanyi Ako, Madhu Bhaskaran, Sharath Sriram, Jianqiang Gu, Ranjan Singh

Advanced Optical Materials· Volume 12· Issue 36

Abstract

Abstract Harnessing confined light on a subwavelength scale within Fano metasurfaces enhances light‐matter interaction on a flexible, low‐loss substrate. This approach enables the integration of ultra‐thin semiconducting films for designing low‐power, ultrafast switchable terahertz, and optical meta devices. Here, an ultra‐thin, ∼λ/6000 germanium overlayers of 25nm or 50nm is thermally evaporated onto a flexible Fano metallic metasurface to achieve ultrafast optical modulation of terahertz radiation. A remarkable 85% modulation depth with an ultrafast speed of 400 GHz is obtained in the resonant transmission. These ultrathin, flexible, and ultrafast functional metasurfaces pave the way for developing flexible terahertz active meta devices based on nanometric scale germanium films, offering the additional advantage of compatibility with complementary metal‐oxide‐semiconductor (CMOS) technology in microelectronics.
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Research context

OpenAlex topics: Metamaterials and Metasurfaces Applications · Plasmonic and Surface Plasmon Research · Terahertz technology and applications

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore

Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering Tianjin University Tianjin 300072 China

Centre for Disruptive Photonic Technologies The Photonics Institute Nanyang Technological University Singapore 637371 Singapore

Department of Physics Indian Institute of Technology Hyderabad Kandi Sangareddy Telangana 502285 India

Functional Materials and Microsystems Research Group and the Micro Nano Research Facility ARC Centre of Excellence for Transformative Meta‐Optical Systems RMIT University Melbourne VIC 3000 Australia

Department of Electrical Engineering University of Notre Dame Notre Dame IN 46556 USA

Funding

Australian National Fabrication Facility

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