Gas sensors are important in many fields such as environmental monitoring, agricultural production, public safety, and medical diagnostics. Herein, Tamm plasmon resonance in a photonic bandgap is used to develop an optical gas sensor with high performance. The structure of the proposed sensor comprises a gas cavity sandwiched between a one-dimensional porous silicon photonic crystal and an Ag layer deposited on a prism. The optimised structure of the proposed sensor achieves ultra-high sensitivity (S = 1.9×10⁵ nm/RIU) and a low detection limit (DL = 1.4×10⁻⁷ RIU) compared to the existing gas sensor. The brilliant sensing performance and simple design of the proposed structure make our device highly suitable for use as a sensor in a variety of biomedical and industrial applications.

A new biophotonic sensor based on photonic crystal (PC) has been designed for the detection of creatinine concentration in blood, and is considered an important small molecule biomarker of renal dysfunction. Based on the transfer matrix method (TMM), we theoretically investigated the transmittance spectra of a one dimensional alternating dielectric photonic crystal (PC) designed as (AB)⁷/C/(AB)⁷ made of MgF₂ (A), CeO₂ (B) and creatinine concentration present in blood (C). The transmission spectra exhibit resonant peaks within the photonic band gap (PBG) indicative of so-called defect modes, which depend on parameters, such as concentration of creatinine in blood, thickness of defect layer and incident angle. The proposed sensor can determine the physiological levels of creatinine in human blood serum samples. The estimated parameters realize an efficient biophotonic sensor wherein sensitivity was tuned from 136.4 nm per RIU to 306.25 nm per RIU and is very useful for the detection of creatinine.

Photonic sensing is a novel technology and accurate measurement for biosensing applications. The present work proposes a defective one-dimensional photonic crystal (1D-PC) based on Si/SiO ₂ -layers with a central liquid-filled defect layer as a blood sugar concentration biosensor in the visible region. The transmission spectrum is calculated numerically by using the transfer matrix method. The thickness of the defect layer and incident angle are optimized to achieve the best performance of the sensor. The results show that the localization of defect mode shifts to a longer wavelength with increasing the defect layer thickness. In addition to increasing the incident angle from θ ₀ = 0° to θ ₀ = 90°, the defect peak was shifted towards the short wavelength region. The optimized value of our structure demonstrates high sensitivity for the blood sugar ( S = 1100 nm/RIU) in the range of concentration 0–500 mg dl ⁻¹ , more enhancement of the quality factor (3.539 × 10 ⁶ ) and very low limit of detection (8.8 × 10 ⁻⁹ RIU) are achieved. Our results indicate that the proposed structure has higher performance as a blood sugar sensor than many previously reported data. Besides, the simplicity of the proposed structure makes it favorable to the industrial design using inexpensive and massive product nanofabrication techniques.