Design and modeling of eye-shaped double-slot GaAs microring resonator for CO2 sensing
Scientific Reports, vol.15, no.1, 2025 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 15 Issue: 1
- Publication Date: 2025
- Doi Number: 10.1038/s41598-025-17208-6
- Journal Name: Scientific Reports
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, BIOSIS, Chemical Abstracts Core, MEDLINE, Veterinary Science Database, Directory of Open Access Journals
- Keywords: CO2 detection, Double-slot waveguide, Gas sensor, Microring resonator, Monitoring CO2 levels, VarFDTD method
- Eskisehir Osmangazi University Affiliated: Yes
Abstract
Monitoring of CO2 is crucial because of its profound impact on both environmental and human health. A novel highly sensitive refractive index (RI) sensor, utilizing a double-slot microring resonating structure, has been designed and numerically assessed for the sensitive detection of gas media. The structure consisted of a circular microring resonator nested in a racetrack resonating configuration mimicking the structure of an eye-shaped microring resonator (ESMRR). This system was simulated and designed for a GaAs double-slot core waveguide deposited on a suitable Al0.5Ga0.5As substrate. Optical transfer function of ESMRR and related equations were derived using Mason rule, while the numerical analysis was performed using the variational finite difference time domain (var- FDTD) method. The free spectral range (FSR) was extended to 137.68 nm that led to a remarkable bulk sensitivity of 1217.39 nm/RIU and a resolution of 4.93 × 10−6 RIU. The proposed sensing structure was envisioned for CO2 sensing and demonstrated an impressive sensitivity of 24.4 pm/ppm for CO2 detection with an estimated detection limit of 0.82 ppm.