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.

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Refractive index gas sensor based on the Tamm state in a one-dimensional photonic crystal: Theoretical optimisation.

The paper proposes an ultra-narrow band graphene refractive index sensor, consisting of a patterned graphene layer on the top, a dielectric layer of SiO2 in the middle, and a bottom Au layer. The absorption sensor achieves the absorption efficiency of 99.41% and 99.22% at 5.664 THz and 8.062 THz, with the absorption bandwidths 0.0171 THz and 0.0152 THz, respectively. Compared with noble metal absorbers, our graphene absorber can achieve tunability by adjusting the Fermi level and relaxation time of the graphene layer with the geometry of the absorber unchanged, which greatly saves the manufacturing cost. The results show that the sensor has the properties of polarization-independence and large-angle insensitivity due to the symmetric structure. In addition, the practical application of testing the content of hemoglobin biomolecules was conducted, the frequency of first resonance mode shows a shift of 0.017 THz, and the second resonance mode has a shift of 0.016 THz, demonstrating the good frequency sensitivity of our sensor. The S (sensitivities) of the sensor were calculated at 875 GHz/RIU and 775 GHz/RIU, and quality factors FOM (Figure of Merit) are 26.51 and 18.90, respectively; and the minimum limit of detection is 0.04. By comparing with previous similar sensors, our sensor has better sensing performance, which can be applied to photon detection in the terahertz band, biochemical sensing, and other fields.

/pdf/design-of-ultra-narrow-band-graphene-refractive-index-sensor-15gyt2xt.pdf

Design of Ultra-Narrow Band Graphene Refractive Index Sensor

Recent advancements in optical biosensors for cancer detection.

Recent advancements in optical biosensors for cancer detection

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.

/pdf/biophotonic-sensor-for-the-detection-of-creatinine-3xwtvwsajg.pdf

Biophotonic sensor for the detection of creatinine concentration in blood serum based on 1D photonic crystal

Photonic sensing is a new technology and accurate measurement for biosensing applications. The present work has been proposed blood sugar biosensor in the visible region by using a defective one-dimensional photonic crystal (1D-PC). The structure adopted is Air/(SiO2/Si)^5/SiO2/D/SiO2/(SiO2/Si)^5/ SiO_2substrate. The defect layer (D) is filled with blood sugar solution with different concentrations. The transmission spectrum was calculated numerically by using the transfer matrix method (TMM). The thickness of the defect layer and incident angle has been optimized to achieve the best performance of the sensor. The localization of defect mode shifts to a longer wavelength with increasing the defect layer thickness. In addition to increase the incident angle from θ_0=0 to θ_0=90 degree, 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 range of concentration C=0 to C=500 mg/dl, more enhancement of the quality factor (about 3.755*106) and very low detection limit (DL=10^(-8) RIU) are achieved. These results indicate that the proposed structure has higher performance as a blood sugar sensor than many previously reported data.

https://iopscience.iop.org/article/10.1088/1402-4896/ab53f5/pdf

Theoretical study of hybrid multifunctional one-dimensional photonic crystal as a flexible blood sugar sensor

Ultra-sensitive photonic crystal cancer cells sensor with a high-quality factor

In this paper, nanoscale pores in silicon layers are exploited to model and optimize a one-dimensional hybrid graphene-porous silicon photonic crystal biosensor. The physical nature of the proposed sensor is based on Tamm resonance. The transfer matrix method is applied to detect the change of the index of refraction in an aqueous solution. The proposed model is (PSi1/PSi2)N/G/Substrate, in which PSi1 and PSi2 are porous silicon layers with different porosities, N is the number of periods, and G is the number of graphene layers. The numerical simulations show that the proposed sensor has good performance. The variation of the number of periods, number of graphene layers, porosities, thicknesses of silicon layers, incident angles, and the sample layer thickness affect the performance of the sensor. By varying these parameters, the sensitivity and figure of merit of the sensor can be controlled. The study shows that the sensitivity and figure of merit of the proposed sensor reach 4.75 THz/RIU and 475RIU−1, respectively. The proposed sensor has a good capability in biological detection within terahertz. It is the first time, to our knowledge, that graphene has been used to excite the Tamm resonance using the photonic crystal of porous silicon and using it in biosensing applications.

Modeling of a biosensor using Tamm resonance excited by graphene

One-dimensional hybrid photonic crystal made of a superconductor (YBa2Cu3O7) nanocomposite and dielectric material (silicon) is theoretically investigated by the two-fluid model and the transfer matrix method based on Tamm resonance The structure consists of a ternary photonic crystal capped by metallic layer Ag Interesting multi-photonic band gaps are achieved for a suitable hybrid periodic system The characteristic of these multi-photonic band gaps can be manipulated by the temperature of the system The proposed sensor records high sensitivity (from 11 to 22 nm/K), very high signal-to-noise (from 24 to 125), and low resolution (from 011 to 014) Compared with previous works, our proposed sensor can achieve high sensitivity for near-zero (K) temperature sensing

Zaky A. Zaky

Papers

Refractive index gas sensor based on the Tamm state in a one-dimensional photonic crystal: Theoretical optimisation.

Theoretical study of hybrid multifunctional one-dimensional photonic crystal as a flexible blood sugar sensor

Ultra-sensitive photonic crystal cancer cells sensor with a high-quality factor

Modeling of a biosensor using Tamm resonance excited by graphene

Theoretical Study of a Tunable Low-Temperature Photonic Crystal Sensor Using Dielectric-Superconductor Nanocomposite Layers