Terahertz Active Photonic Crystals for Condensed Gas Sensing

Benz, A.; Deutsch, C.; Brandstetter, Markus; Andrews, A. M.; Klang, P.; Detz, Hermann; Schrenk, W.; Strasser, G.; Unterrainer, K.

doi:10.3390/s110606003

Cited by 34 publications

(11 citation statements)

References 61 publications

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“…They are sensitive, easy to use and immune to electromagnetic interference. In particular, label‐free detection for refractive index change is attracting extensive interests , including waveguide sensors , resonator sensors , photonic crystal sensors , nanowire sensors , fiber sensors , plasmonic sensors , and metamaterial sensors . No matter which type of sensors, the aim is to maximize the interaction between light and analytes.…”

Section: Introductionmentioning

confidence: 99%

Metamaterial absorber integrated microfluidic terahertz sensors

Wen

et al. 2016

Laser & Photonics Reviews

255

130

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Spatial overlap between the electromagnetic fields and the analytes is a key factor for strong light-matter interaction leading to high sensitivity for label-free refractive index sensing. Usually, the overlap and therefore the sensitivity are limited by either the localized near field of plasmonic antennas or the decayed resonant mode outside the cavity applied to monitor the refractive index variation. In this paper, by constructing a metal microstructure array-dielectric-metal (MDM) structure, a novel metamaterial absorber integrated microfluidic sensor is proposed and demonstrated in terahertz (THz) range, where the dielectric layer of the MDM structure is hollow and acts as the microfluidic channel. Tuning the electromagnetic parameters of metamaterial absorber, greatly confined electromagnetic fields can be obtained in the channel resulting in significantly enhanced interaction between the analytes and the THz wave. A high sensitivity of 3.5 THz/RIU is predicted. The experimental results of devices working around 1 THz agree with the simulation ones well.The proposed idea to integrate metamaterial and microfluid with a large light-matter interaction can be extended to other frequency regions and has promising applications in matter detection and biosensing.2

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Section: Introductionmentioning

confidence: 99%

Metamaterial absorber integrated microfluidic terahertz sensors

Wen

et al. 2016

Laser & Photonics Reviews

255

130

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“…The other method of THz gas sensing is to use the THz resonance field in the photonic or periodic structures [18,19]. For example, one-and two-dimensional photonic structures respectively based on the silicon slabs [18] and pillar arrays [19] have been validated for the non-specific gas sensing in the THz frequency range. The proposed photonic structures have high-quality factors on THz field resonance and are sensitive to slight changes of refractive index.…”

Section: Introductionmentioning

confidence: 99%

Optical Gas Sensors Using Terahertz Waves in the Layered Media

You¹,

Lu²

2020

Gas Sensors

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Terahertz (THz) wave propagation in the layered media is presented based on the waveguide and artificial-material configurations to sense the gas molecules. The single dielectric layer with a cylindrical conformation works as a pipe waveguide in the wave frequency of 0.1-1 THz. For a long-distance propagation over 10 cm of the pipe, resonant modes are characterized from the transmission power dips. The pipe-waveguide resonator works for a THz refractive-index sensor when the resonance frequency is monitored to sense vapor molecules inside the pipe core. Besides of the waveguide configuration, a multilayer microporous polymer structure (MPS) is considered an artificial material to transmit THz waves for sensing gaseous molecules. The MPS is not only transparent to THz waves but also enhances the detection resolution of THz absorption for the vapor molecules. The porous structure provides a large hydrophilic surface area and numerous micropores to adsorb or fill vapors, thereby leading to greatly enhanced wave-analyte interaction with an apparent THz signal change. Different concentrations of toxic methanol adulterated in alcoholic aqueous solutions are thus identified in their vapor phases by using the MPS-based THz sensor.

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“…After their first demonstration, QCLs have become the preferred compact sources in THz region, even though the integration of a THz source and detector is still challenging. Nevertheless, they are essential for applications in THz imaging and sensing, while their ability to operate in continuous wave regime makes them suitable for high resolution THz spectroscopy [13,14]. Metal-metal THz QCL waveguides are the most suitable platform for active THz CRLM metamaterial implementation [4].…”

Section: Introductionmentioning

confidence: 99%

Possibilities of achieving negative refraction in QCL-based semiconductor metamaterials in the THz spectral range

et al. 2014

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This is a repository copy of Possibilities of achieving negative refraction in QCL- ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request.-1- Possibilities of achieving negative refraction in QCL- Abstract:One of the challenges in the design of metamaterialsÕ unit cells is the reduction of losses caused by the metallic inclusions. In order to overcome this obstacle, it has been proposed to use the active medium as the unit cell. Quantum cascade lasers are great candidates for the active medium materials since they are able to provide high values of optical gain. In this paper we investigate and compare two quantum cascade structures optimized for emission frequencies lower than 2 THz and simulate the effect of a strong magnetic field applied perpendicularly to the layers.Comprehensive description of conduction-band nonparabolicity is used to calculate the electronic structure, and subsequently evaluate the longitudinal optical phonon and interface roughness scattering rates and solve the system of rate equations which govern the distribution of carriers among the Landau levels. Once we assess the degree of population inversion, we have all the necessary information about the permittivity component along the growth direction of the structure and may determine the conditions under which the structure displays negative refraction.

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Terahertz Active Photonic Crystals for Condensed Gas Sensing

Cited by 34 publications

References 61 publications

Metamaterial absorber integrated microfluidic terahertz sensors

Metamaterial absorber integrated microfluidic terahertz sensors

Optical Gas Sensors Using Terahertz Waves in the Layered Media

Possibilities of achieving negative refraction in QCL-based semiconductor metamaterials in the THz spectral range

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