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An efficient refractive index (RI) biosensor based on the structure of side-coupled microcavity two-dimensional photonic crystal (2DPC) is presented. The biosensor is intended to accurately identify blood constituents that have different RIs. The calculated transmittance spectrum of the sensor, in the presence of an analyte, demonstrates a resonant peak within the photonic bandgap (PBG) region. The resonance wavelength shifts to higher values in response to the increase in the analyte RI. The transmittance efficacy at the resonant wavelength is found to be approximately 91% with the resonant peak exhibiting a line width of 1.4 nm. The sensitivity (S), quality factor (Q), and detection limit (DL) are quantitatively assessed, yielding values of 670 nm per refractive index unit (nm/RIU), 1053, and 2.1 × 10–4 RIU, respectively. These findings indicate that the proposed structure can be utilized as an efficient biosensor. Moreover, with a size of around 18.95 μmμ2, the biosensor is considered compact and can be easily integrated into electronic circuits. [ABSTRACT FROM AUTHOR]

In this paper, we propose structures for tunable narrow bandpass optical filters covering the visible range of 400–800 nm. The transmittance spectra of s-polarized (TE mode) light in one-dimensional photonic crystals are obtained by using a theoretical calculation based on the transfer matrix method. Here, photonic crystals and photonic quasicrystals composed of Si and SiO2 are organized according to some generations of the Octonacci sequence. The number of output channels and their central wavelengths are found to be dependent on the generation number and the angle of incidence. The results show an increase in the quality factor as the angle of incidence increased. Therefore, the proposed structures are believed to be suitable for efficient narrow bandpass filters operating in the visible range. [ABSTRACT FROM AUTHOR]

The tuning of a defect mode in a photonic crystal (PC) is of high significance for filter and sensor applications. We here investigate the tuning of the defect mode of a defective ternary PC with a semiconductor and high critical-temperature superconductor layers. A ternary photonic crystal with the heterostructure (semiconductor/superconductor/dielectric) is assumed. The transfer matrix method is employed to investigate the transmission of transverse electric waves. The refractive indices of the semiconductor and superconductor layers can be tuned by changing the operating temperature and the hydrostatic pressure. The defect mode and transmission properties can be controlled by using the hydrostatic pressure, operating temperature, frequency and thicknesses of the heterostructure layers. The analysis is performed in the frequency range of 20–65 THz. The proposed structure can be utilized as a biosensor and a narrowband transmission peaks filter. [ABSTRACT FROM AUTHOR]

It is very important to design a rapid and sensitive device for the creatinine concentration detection due to it being one of the most considerable benchmarks for efficient kidney working. Here, a novel biophotonic sensor using one-dimensional ternary PC based on Si/TiN/SiO2 layers is proposed for the creatinine concentration detection in a blood serum sample. A central cavity layer is inserted between two equal periodic numbers. The blood sample can be infiltrated in the cavity layer with various creatinine concentrations. Based on the technique of transfer matrix, the transmittance spectra properties are investigated. The influences of variation of the incidence angle for both TE and TM polarizations and the cavity layer thickness are carefully investigated to attain the best sensitivity of the biophotonic detector. A high sensitivity of 938.02 nm/RIU is realized for the suggested detector, which is comparable to most recent works published in this area. Moreover, the proposed sensor has an inexpensive cost, real-time detection, and simple structure, which is helpful to the industrial design using low-cost product nanofabrication techniques. Based on above-mentioned outcomes, our biosensor candidate is a suitable and effective device for the detection of creatinine concentration, and it can use for any biological sample. [ABSTRACT FROM AUTHOR]