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Cong L, Pitchappa P, Wang N, Singh R. Electrically Programmable Terahertz Diatomic Metamolecules for Chiral Optical Control. RESEARCH 2019; 2019:7084251. [PMID: 31549081 PMCID: PMC6750089 DOI: 10.34133/2019/7084251] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 01/22/2019] [Indexed: 12/31/2022]
Abstract
Optical chirality is central to many industrial photonic technologies including enantiomer identification, ellipsometry-based tomography, and spin multiplexing in optical communications. However, a substantial chiral response requires a three-dimensional constituent, thereby making the morphology highly complex to realize structural reconfiguration. Moreover, an active reconfiguration demands intense dosage of external stimuli that pose a major limitation for on-chip integration. Here, we report a low bias, electrically programmable synthetic chiral paradigm with a remarkable reconfiguration among levorotatory, dextrorotatory, achiral, and racemic conformations. The switchable optical activity induced by the chiral conformations enables a transmission-type duplex spatial light modulator for terahertz single pixel imaging. The prototype delivers a new strategy towards reconfigurable stereoselective photonic applications and opens up avenues for on-chip programmable chiral devices with tremendous applications in biology, medicine, chemistry, and photonics.
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Affiliation(s)
- Longqing Cong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.,Centre for Disruptive Photonic Technologies, The Photonics Institute, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Prakash Pitchappa
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.,Centre for Disruptive Photonic Technologies, The Photonics Institute, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Nan Wang
- Institute of Microelectronics, 11 Science Park Road, 117685, Singapore
| | - Ranjan Singh
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.,Centre for Disruptive Photonic Technologies, The Photonics Institute, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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Liu M, Susli M, Silva D, Putrino G, Kala H, Fan S, Cole M, Faraone L, Wallace VP, Padilla WJ, Powell DA, Shadrivov IV, Martyniuk M. Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial. MICROSYSTEMS & NANOENGINEERING 2017; 3:17033. [PMID: 31057871 PMCID: PMC6445006 DOI: 10.1038/micronano.2017.33] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 04/06/2017] [Accepted: 04/12/2017] [Indexed: 05/27/2023]
Abstract
The realization of high-performance tunable absorbers for terahertz frequencies is crucial for advancing applications such as single-pixel imaging and spectroscopy. Based on the strong position sensitivity of metamaterials' electromagnetic response, we combine meta-atoms that support strongly localized modes with suspended flat membranes that can be driven electrostatically. This design maximizes the tunability range for small mechanical displacements of the membranes. We employ a micro-electro-mechanical system technology and successfully fabricate the devices. Our prototype devices are among the best-performing tunable THz absorbers demonstrated to date, with an ultrathin device thickness (~1/50 of the working wavelength), absorption varying between 60% and 80% in the initial state when the membranes remain suspended, and fast switching speed (~27 μs). The absorption is tuned by an applied voltage, with the most marked results achieved when the structure reaches the snap-down state. In this case, the resonance shifts by >200% of the linewidth (14% of the initial resonance frequency), and the absolute absorption modulation measured at the initial resonance can reach 65%. The demonstrated approach can be further optimized and extended to benefit numerous applications in THz technology.
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Affiliation(s)
- Mingkai Liu
- Nonlinear Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia
| | - Mohamad Susli
- School of Electrical, Electronic and Computer Engineering, the University of Western Australia, Crawley, WA 6009, Australia
| | - Dilusha Silva
- School of Electrical, Electronic and Computer Engineering, the University of Western Australia, Crawley, WA 6009, Australia
| | - Gino Putrino
- School of Electrical, Electronic and Computer Engineering, the University of Western Australia, Crawley, WA 6009, Australia
| | - Hemendra Kala
- School of Electrical, Electronic and Computer Engineering, the University of Western Australia, Crawley, WA 6009, Australia
| | - Shuting Fan
- School of Physics, University of Western Australia, Crawley, WA 6009, Australia
| | - Michael Cole
- Nonlinear Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia
| | - Lorenzo Faraone
- School of Electrical, Electronic and Computer Engineering, the University of Western Australia, Crawley, WA 6009, Australia
| | - Vincent P. Wallace
- School of Physics, University of Western Australia, Crawley, WA 6009, Australia
| | - Willie J. Padilla
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
| | - David A. Powell
- Nonlinear Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia
| | - Ilya V. Shadrivov
- Nonlinear Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia
| | - Mariusz Martyniuk
- School of Electrical, Electronic and Computer Engineering, the University of Western Australia, Crawley, WA 6009, Australia
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