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Wen T, Wan P, Lu C, Zhang D, Gao M, Lin Y, Wen Q, Liao Y, Zhang H, Zhong Z. Tune the resonance of VO 2 joined metamaterial dimers by adjacent cut wires. OPTICS EXPRESS 2022; 30:29379-29387. [PMID: 36299113 DOI: 10.1364/oe.467751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 07/15/2022] [Indexed: 06/16/2023]
Abstract
Two terahertz metamaterials were joined by a conductivity variable VO2 patch to obtain a metamaterial dimer. By applying voltage or heat to the VO2 patches, active modulation of terahertz wave could be achieved. A cut-wire metamaterial was placed adjacent to the VO2 joined dimer to affect its electromagnetic response. It was found that the cut wire could heavily impact the resonance mode of the VO2 joined dimer, which gives dual resonance dips in transmission spectrum for both insulating and conducting states of VO2 patches. As a result, by tuning the conductivity of VO2, active dual band phase modulation could be achieved with high transmission window by this dimer-cut wire coupling system.
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Thomas L, Hannotte T, Santos CN, Walter B, Lavancier M, Eliet S, Faucher M, Lampin JF, Peretti R. Imaging of THz Photonic Modes by Scattering Scanning Near-Field Optical Microscopy. ACS APPLIED MATERIALS & INTERFACES 2022; 14:32608-32617. [PMID: 35802070 DOI: 10.1021/acsami.2c01871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We investigated the near-field distribution associated to the photonic mode of terahertz photonic micro-resonators by scattering scanning near-field optical microscopy. Probing individual THz micro-resonators concentrating electric fields is important for high-sensitivity chemical and biochemical sensing and fundamental light-matter interactions studies at the nanoscale. We imaged both electric field concentration predicted by numerical simulations and unexpected patterns that deviate from intuitive assumptions. We propose a scenario based on the combination of the near-field with the far-field pattern of the probe/resonator ensemble that is in excellent agreement with the experimental data and propose an image analysis procedure to recover the near-field of such structures.
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Affiliation(s)
- Louis Thomas
- Institut d'Electronique, de Microélectronique et de Nanotechnologie, CNRS, Univ. Lille, Villeneuve d'Ascq, 59652 France
| | - Théo Hannotte
- Institut d'Electronique, de Microélectronique et de Nanotechnologie, CNRS, Univ. Lille, Villeneuve d'Ascq, 59652 France
| | - Cristiane N Santos
- Institut d'Electronique, de Microélectronique et de Nanotechnologie, CNRS, Univ. Lille, Villeneuve d'Ascq, 59652 France
| | | | - Mélanie Lavancier
- Institut d'Electronique, de Microélectronique et de Nanotechnologie, CNRS, Univ. Lille, Villeneuve d'Ascq, 59652 France
| | - Sophie Eliet
- Institut d'Electronique, de Microélectronique et de Nanotechnologie, CNRS, Univ. Lille, Villeneuve d'Ascq, 59652 France
| | - Marc Faucher
- Institut d'Electronique, de Microélectronique et de Nanotechnologie, CNRS, Univ. Lille, Villeneuve d'Ascq, 59652 France
| | - Jean-François Lampin
- Institut d'Electronique, de Microélectronique et de Nanotechnologie, CNRS, Univ. Lille, Villeneuve d'Ascq, 59652 France
| | - Romain Peretti
- Institut d'Electronique, de Microélectronique et de Nanotechnologie, CNRS, Univ. Lille, Villeneuve d'Ascq, 59652 France
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Bejide M, Li Y, Stavrias N, Redlich B, Tanaka T, Lam VD, Tung NT, Janssens E. Transient transmission of THz metamaterial antennas by impact ionization in a silicon substrate. OPTICS EXPRESS 2021; 29:170-181. [PMID: 33362107 DOI: 10.1364/oe.405555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/08/2020] [Indexed: 06/12/2023]
Abstract
The picosecond dynamics of excited charge carriers in the silicon substrate of THz metamaterial antennas was studied at different wavelengths. Time-resolved THz pump-THz probe spectroscopy was performed with light from a tunable free electron laser in the 9.3-16.7 THz frequency range using fluences of 2-12 J/m2. Depending on the excitation wavelength with respect to the resonance center, transient transmission increase, decrease, or a combination of both was observed. The transient transmission changes can be explained by local electric field enhancement, which induces impact ionization in the silicon substrate, increasing the local number of charge carriers by several orders of magnitude, and their subsequent diffusion and recombination. The studied metamaterials can be integrated with common semiconductor devices and can potentially be used in sensing applications and THz energy harvesting.
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Pizzuto A, Mittleman DM, Klarskov P. Laser THz emission nanoscopy and THz nanoscopy. OPTICS EXPRESS 2020; 28:18778-18789. [PMID: 32672171 DOI: 10.1364/oe.382130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/28/2020] [Indexed: 06/11/2023]
Abstract
We present an experimental and theoretical comparison of two different scattering-type scanning near-field optical microscopy (s-SNOM) based techniques in the terahertz regime; nanoscale reflection-type terahertz time-domain spectroscopy (THz nanoscopy) and nanoscale laser terahertz emission microscopy, or laser terahertz emission nanoscopy (LTEN). We show that complementary information regarding a material's charge carriers can be gained from these techniques when employed back-to-back. For the specific case of THz nanoscopy and LTEN imaging performed on a lightly p-doped InAs sample, we were able to record waveforms with detector signal components demodulated up to the 6th and the 10th harmonic of the tip oscillation frequency, and measure a THz near-field confinement down to 11 nm. A computational approach for determining the spatial confinement of the enhanced electric field in the near-field region of the conductive probe is presented, which manifests an effective "tip sharpening" in the case of nanoscale LTEN due to the alternative geometry and optical nonlinearity of the THz generation mechanism. Finally, we demonstrate the utility of the finite dipole model (FDM) in predicting the broadband scattered THz electric field, and present the first use of this model for predicting a near-field response from LTEN.
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