The proposed optical gas sensor is based on the principle of electromagnetically induced transparency (EMT), which is a quantum interference phenomenon that occurs when two closely spaced resonant modes interact with an intermediate level. In our design, we use plasmonic corrugated ring resonators that resonate in the mid-infrared (MIR) wavelength range, which is of particular interest because it contains the absorption resonance for several gas molecules such as methane, carbon dioxide, carbon monoxide, and acetone. We propose a slotted waveguide coupled with a slotted corrugated ring resonator, which is etched inside a doped silicon wafer on sapphire. Doped silicon is a better alternative to noble metals for plasmonic techniques in the MIR region. By optimizing the corrugated and ring to resonate at the same wavelength, we observe interesting phenomena such as Fano-resonance and EIT effects. The EIT effect causes the absence of resonant spectral lines at the same wavelength and the creation of two resonance lines at red-shifted and blue-shifted wavelengths. This effect is useful in gas sensing because it provides a sharp and narrow transmission peak that enables precise detection of gas molecules. In our paper, we provide details about the dimensions and materials used in our design. We demonstrate that our sensor achieves a small footprint, high sensitivity, and high Figure of merit. The small footprint makes our sensor suitable for integration into compact devices, while the high sensitivity and Figure of merit make it ideal for accurate and reliable gas sensing applications.
KEYWORDS: Data modeling, Machine learning, Education and training, Resonators, Silicon, Temperature metrology, Microrings, Microresonators, Bioalcohols, Water
An approach to measuring chemical concentrations using a micro-ring resonator (MRR) is proposed which is robust to thermo-optic noise and spectral shifts caused by temperature changes. The method uses a modified ResNet50 with varied kernel size and achieved a mean-square error (MSE) of 4.548E-4, and performance is compared to other machine learning methods including VGG20 and XGBoost. The model was trained to read the transmission spectra of a slotted MRR etched into heavily doped silicon and output the concentrations of chemicals in the surrounding analyte. The chemicals tested on were water, ethanol, methanol, and propanol, with concentrations ranging from 0-100%, with a dataset containing . This occurs over the mid-infrared wavelengths and within the temperature range of 290-310 K. Transfer learning was also utilized to retrain the models on several other datasets, consisting of 528 transmissions each. These datasets operated over different temperature ranges (310-320), and the other with a different set of chemicals, (water, ethanol, methanol and butanol). Similar results were achieved, with both networks achieving similar MSE. We then perform the same process on another design with the same chemicals, also operating over the infrared range, demonstrating the robustness of the method. All datasets used in the study were obtained through simulation, although we hope to test on real data.
A novel optical gas sensor based on electromagnetically induced transparency (EMT)is proposed. In this paper we propose plasmonic non concentric ring resonators resonate near the absorption regions of many gases in the mid-infrared region. Mid-infrared (MIR) wavelength range is of particular interest because it contains the absorption resonance for several molecules such as methane, carbon dioxide, carbon monoxide, and acetone. The sensing process is controlled by changing the refractive index. The proposed slotted waveguide coupled with double non-concentric ring resonators, both the waveguide and rings are surrounded with doped silicon. Doped silicon can act as a suitable plasmonic alternative instead of metals in the MIR range. When the two coupled non-concentric rings optimize to resonate on the same wavelength; interesting phenomena occurs such as the Fano-resonance and the electromagnetic induced transparency effects. In this paper we show the electromagnetic induced Transparency which is an absence of the resonant spectral lines of the same wavelength, and the creation of two resonance lines at red-shifted and blue-shifted wavelengths. Moreover, we mentioned all the details about the dimensions and the material used for our design. A Small foot print, high sensitivity, and high Figure of merit are achieved.
We propose various optical ring gas sensors. These gas sensors are promising candidates for integrated on-chip sensing. The sensing operation depends on the change in the effective index. We show a detailed study of different sensors utilizing the absorption wavelength of both methane and carbon dioxide gases. These sensors mainly operate at the range of mid-infrared wavelengths because it contains the vibrational resonance of the gases of interest. We provide the details about the dimensions and the material used in our different structures. Moreover, we report sensitivity up to 5938 nm / RIU, and the full-width-half maximum (FWHM) and figure of merit (FoM) for all designs are also calculated. We succeeded in squeezing the FWHM to 4.76 nm and increasing the FoM to 1744.72.
Mid-infrared (MIR) region is an important region for sensing applications because it contains vibrational resonance for many gases such as methane, carbon monoxide, carbon dioxide, sulfuric acid, ammonia, and acetone. Doped silicon with negative permittivity in MIR region can be used in plasmonic technology to design gas sensors which combining both benefits of silicon and plasmonic technology in MIR region. Fabricating plasmonic integrated devices became easier with current progress in Nanotechnology. Small foot print could be achieved by using Plasmonics technology. Additionally, silicon is CMOS compatible, tunable, and it has high mobility. In this paper we proposed a Fabry-Perot resonator made of doped silicon. Moreover, we studied the response of the Fabry-Perot resonator as a gas sensor in the presence of air, methane and carbon dioxide gases. Consequently, the sensitivity, quality factor and the figure of merit are calculated.
We propose devices based on doped silicon. Doped silicon is designed to act as a plasmonic medium in the midinfrared (MIR) range. The surface plasmon frequency of the doped silicon can be tuned within the MIR range, which gives rise to useful properties in the material’s dispersion. We propose various plasmonic configurations that can be utilized for silicon on-chip applications in MIR. These devices have superior performance over conventional silicon devices and provide unique functionalities such as 90-sharp degree bends, T- and X-junction splitters, and stubs. These devices are CMOS-compatible and can be easily integrated with other electronic devices. In addition, the potential for biological and environmental sensing using doped silicon nanowires is demonstrated.
The mid-infrared (MIR) region is one of the most thriving spectral regions as it contains the vibrational resonances of several molecules of interest, as well as the absorption bands for hot bodies. In this work, we propose a novel dielectric waveguide that confines the light in a nanoscale air gap. This dielectric waveguide is a suitable candidate for on-chip sensing. Detailed dispersion analysis of this 3D waveguide is also provided. The effect of the refractive index change in the gap is studied and shows very high sensitivity and causes significant changes in the modal parameters. We also show that these waveguide modes exhibit plasmonic-like characteristics at the MIR region with controllable plasma frequency, without the inclusion of any metals. This waveguide is also utilized in various on-chip applications with nanoscale confinement at the MIR region.
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