This study explores the tunable infrared filtering properties of a one-dimensional (1D) defective photonic crystal (PhC) featuring a pressure-sensitive polymer defect layer. Using the transfer matrix method, we examine a multilayer structure of Gallium Arsenide (GaAs) and Silica (SiO₂), incorporating defect layers of Polystyrene (PS), Polymethyl Methacrylate (PMMA), and Ammonium Dihydrogen Phosphate (ADP). Hydrostatic pressure alters these polymers’ refractive indices, shifting the transmission spectra’s localised defect mode. Results show that increasing pressure narrows the photonic band gap and reduces the quality factor, with PS exhibiting the increased pressure sensitivity. Conversely, increasing defect layer thickness improves the transmittance peak and quality factor, with PMMA showing the best thickness-based tunability. These outcomes offer valuable insights into pressure-dependent optical tuning and demonstrate the potential of these structures in developing compact, tunable IR filters for advanced photonic, optical sensing, and optoelectronic applications across a broad spectral range.

In the present research work, the dependency of the defect mode properties on the position of a nanocomposite defect layer in an asymmetric ternary photonic crystal (ATPC) is theoretically investigated using the pioneer transfer matrix method [TMM]. The ATPC has the structure (ABC)N/D/(ABC)N, where N is the number of periods. Layers A, B, and C are Silicon (Si), Silicon nitride (Si3N4), and Polystyrene (C8H8)n, respectively. D is the defect layer of nanocomposite material consisting of silica and silver nanoparticles. In this paper, we inserted the nanocomposite defect layer at different positions in an optical photonic structure containing a 2N + 1 repetitive layer. We have presented and numerically analyzed the influence of various parameters such as defect layer thickness and filling factor (f) of nanocomposite defect layer on the defect mode properties such as centre wavelength, full-width half maximum, transmittance, and quality factor in the transmission spectrum. We found that out of the five positions considered, the defect mode properties are best for the nanocomposite defect layer inserted between the N and N + 1 repetitive layer. Hence, it is also better than the defect layer inserted at the middle position. The proposed photonic structure has prominent applications such as optical reflectors, polarizers, filters, and switches.

In the present work, a highly sensitive optical pressure sensor based on one dimensional ternary Dodecanacci photonic crystal is proposed. The reported device is a pressure tunable 1D ternary photonic crystal using Dodecanacci sequence with graded layer thickness which depends on the law: y = α x^β where α, β are chosen as the modulation parameters. The materials used are Silicon, Titanium Dioxide and Silicon Dioxide. The appeared resonant peak within the photonic band gap is highly affected by the external hydrostatic pressure. The transmission spectra reflect that the localized peak is highly blue shifted because of pressure enhancement. The key factor is that the dielectric properties of all three materials used are drastically changed by the photo elastic constants. The sensitivity of the device rises exponentially with the raise of α deformation parameter. The optimized values of the α and β parameters are 10–6 and β = 8.10^ - 6 , respectively. The ultimate sensitivity achieved due to modulation parameter and pressure tenability is 19.40 nm/GPa. The proposed novel optical pressure sensor will be useful in various areas such that multichannel mirrors, filters, biosensing, aerospace and gas sensing. The proposal may be also potential applications for optical, photonic devices and optical communication system.

In this research, a one-dimensional photonic crystal with such a novel and simple design is introduced to serve as an efficient reflector for infrared (IR) wavelengths. The construction of the proposed photonic crystal design based on the gyroidal geometry is the mainstay of this research to investigate the total reflectivity through a wide band of IR wavelengths. In this regard, [Air/(A/B) 10 /substrate] is indeed the configuration of the suggested photonic crystal structure. The layer symbols, A and B represent two layers of silver with a gyroidal configuration in host materials of titanium dioxide and silicon, respectively. Meanwhile, our numerical findings demonstrate the existence of a cutoff feature at a wavelength of 1[Formula: see text][Formula: see text]m of the propagating electromagnetic waves. Moreover, the filling fraction of sliver through layers (A) and (B) provides a substantial role in the tunability of the cutoff frequency and the reflectivity of the structure as well. Then, we have taken into account how the host material’s thicknesses and refractive indices will affect the proposed structure’s reflectance. In particular, the refractive index of the host material could lead to a significant variation of the permittivities of the considered materials. Finally, we think that the proposed structure may be of a great interest in a variety of physical and engineering applications including the optical reflectors, smart windows and solar cells applications as well.

In the current work, a design of extremely high performance pressure sensor is achieved using the photonic devices structure as (Bg4/Oct3/Bg4), where Oct3 represents the third generation of the quasi-regular Octonacci sequence and Bg4 is taken as (ABC)4. Herein, the ternary photonic crystal consists layer A of Hg-1223 superconductor, the layer B as GaAs semiconductor and layer C as Silicon (Si), respectively. The transfer matrix method is used to analyses the transmission characteristics for the defect mode. Also, a blue shift is observed for defect mode. The present work shows a comparative investigation of the performance of the proposed designs such as (Oct3/Bg4/Oct3) and (Bg4/Oct3/Bg4). Herein, highlight a tangible impact of the external hydrostatic pressure on the performance of each sensor. A quantitative analysis of the sensitivity of the considered photonic devices is carried out. Furthermore, the findings of this work show a great impact of the sequence's order on the sensor performance. The outcomes of this paper prove that the sensitivity of the device (Oct3/Bg4/Oct3) reaches 9.45 nm/GPa and with a simple conversion of the sequence's order the sensitivity of the photonic device (Bg4/Oct3/Bg4) increases to 10.75 nm/GPa. The proposed novel device will be well-suited for development of the tunable multichannel filters, switches and bio-sensing applications. Moreover, this compact photonic device will be highly useful in the gas and biomolecule sensing fields.

This study investigates using the phononic crystal with periodically closed resonators as a greenhouse gas sensor. The transfer matrix and green methods are used to investigate the dispersion relation theoretically and numerically. A linear acoustic design is proposed, and the waveguides are filled with gas samples. At the center of the structure, a defect resonator is used to excite an acoustic resonant peak inside the phononic bandgap. The localized acoustic peak is shifted to higher frequencies by increasing the acoustic speed and decreasing the density of gas samples. The sensitivity, transmittance of the resonant peak, bandwidth, and figure of merit are calculated at different geometrical conditions to select the optimum dimensions. The proposed closed resonator gas sensor records a sensitivity of 4.1 Hz m−1 s, a figure of merit of 332 m−1 s, a quality factor of 113,962, and a detection limit of 0.0003 m s−1. As a result of its high performance and simplicity, the proposed design can significantly contribute to gas sensors and bio-sensing applications.

Monitoring the variations in pressure, distribution, and the magnitude of the emitted gases at the ground surface is very important in different applications. Because of the parity-time symmetric mechanism, a novel one-dimensional photonic crystal as a pressure sensor is proposed. The transmittance spectra are calculated and analyzed using the transfer matrix method. The parity-time symmetric property amplifies the transmittance of the defect mode and gives an additional hand to enhance the magnification and performance of the sensor. The optimum conditions are the normal angle of incidence, defect layer thickness of 1400 nm, the porosity of the porous silicon layer of 80%, and macroscopic Lorentz oscillation intensity of 5 × 10 -4 . The results show that the position and amplitude sensitivities are 4.9 nm GPa −1 and 1844%/GPa. That means in such sensors, by altering pressure, the desired value of magnified transmittance and sensitivity can be achieved as required according to the optical communication devices. Therefore, the proposed device performs better with high precision and accuracy. Consequently, it is much more helpful in optical communication and optoelectronic devices.

A theoretically and numerically photonic crystal structure with parity-time symmetry is investigated to realize the design of a biomedical sensor for biosensing applications. The transmittance spectra of the structure are investigated, and various performance parameters are evaluated. Different structure parameters such as the unit cell number, the thickness of the sample layer, macroscopic Lorentz oscillation intensity in the PT-symmetry unit cell, the porosity of gallium nitride, and incident angle are theoretically and numerically investigated. To improve the performance of the device, an optimization technique is used. The relatively high sensitivities of 496 nm RIU (the change in the resonant peak wavelength per refractive index unit) and 1002142%/RIU (the change in the transmittance of the resonant peak per refractive index unit) are achieved. The proposed device can be a relatively high-precision detection device for biosensing applications.

A one-dimensional binary photonic crystal (BPC) with an inverted symmetry is presented as a methanol sensor. The BPC is assumed to have the structure (Si/SiO2)(N) (SiO2/Si)(N), where N is the number of periods. The silicon herein used is porous and the measurand is assumed to be infiltrated into the porous network of the silicon material and the air inside the void space of the ensemble is replaced by a chemical compound with a higher refractive index. This leads to an enhancement in the effective refractive index of the structure and as a result, a redshift of the Bragg peak is observed. The transmission spectra tuning can accurately determine the type of chemical compound that is present in the silicon pores. The structure, as a chemical sensor for the detection of methanol, is investigated with variable porosity, layer liquid fraction, porous layer thickness, and angle of incidence. These parameters play a key role in the performance of the proposed device. A sensitivity of 1186.1 nm/RIU has been reached with the current sensor which is extremely high. This device can become a milestone for the detection of liquids and gases for industrial or commercial purposes.

A dielectric superconductor binary photonic crystal (PC) is investigated as an optical sensor for detecting Escherichia coli (E. coli) bacteria. The structure of the proposed PC is (Si $${/}$$ superconductor)N(E. coli) $${/}$$ (Si $${/}$$ superconductor)N. Four different high critical temperature superconductors are employed in the structure. These superconducting materials have temperature- and frequency-dependent refractive indices. Transmission spectra of the PC are investigated and the sensitivity to E. coli bacteria is found to be 165.735 nm $${/}$$ RIU. The sensitivity dependences on the thickness of the defect layer and superconductor material, operating temperature and angle of incidence are investigated. The sensitivity, figure of merit and quality factor are 296.754 nm $${/}$$ RIU, 27936.5 RIU−1 and 66913, respectively, when optimum values of these parameters are employed. It is also found that the superconductor Bi2Sr2Ca2Cu3O10, which has the lowest London penetration length, corresponds to the highest sensitivity.

Light absorption is essential in the construction of photodetectors and photovoltaic applications. In this work, the absorption properties of a defective photonic crystal are analyzed in the GHz region using the transfer matrix method. The defect layer is assumed to be a metamaterial of negative optical parameters sandwiched between two sheets of graphene. The tunable properties of absorption are investigated with the graphene chemical potential and phenomenological scattering rate and the thickness of the metamaterial layer. The results reveal that the number, position and height of the absorption resonant peaks are tuned by graphene optical properties. The spectra are studied with and without graphene sheets and an extra peak is created when two sheets of graphene are inserted on both sides of the metamaterial. The proposed photonic device can be useful in designing graphene and metamaterial-based optical devices such as absorbers, filters and sensors in the GHz region.

Photonic crystals have shown an interesting performance as chemical, biochemical and biological sensors. The proposed chemical sensor is based on a ternary photonic crystal (TPC) which is employed to detect water concentration in ethanol solution. The proposed TPC has alternate layers of glass, dielectric and semiconductor material with ethanol solution as a defect layer. The transmission spectra of the TPC at normal and oblique incidence are calculated and analyzed. The dependence of the refractive index on temperature and concentration of the ethanol solution plays a key role in the principle of operation of the sensor. The effects of the defect layer thickness, angle of incidence, temperature and concentration of ethanol layer are investigated to enhance the performance of the nano chemical sensor. The optimized parameters are employed to achieve a sensitivity of 144.369 nm/RIU. The proposed TPC has a set of advantages such as tunable design, simple structure, and rapid and real-time detection. The proposed sensor can be applied to any kind of biochemical and chemical sensing.

Tunable terahertz (THz) filtering properties of a single channel filter are investigated. The filter structure is based on a defective photonic crystal. The defect layer is assumed as a magnetized plasma medium. The photonic crystal has the structure of (Dielectric–Dielectric)L Plasma (Dielectric–Dielectric)L, where L is the number of unit cells on both sides of the plasma layer. The tunability of the defect mode is studied for various magnetic fields, plasma densities, and thicknesses of the plasma layer. We found that as the applied magnetic field increases, the defect modes shift to a higher frequency. Moreover, the defect modes shift to a shorter frequency as the plasma density or the plasma layer thickness increases. This article provides the theoretical basis for designing a tunable filter or a sensor depending on the parameters used at the THz range.

Biophotonic sensing techniques are an accurate best way for biosensing measurements. The main aim of the proposed device is to make a more effective sensor to detect the change in the refractive index of a sample. This sensor is based on the Tamm–Fano resonance in gold/porous semiconductor photonic crystal. Porous Gallium nitride has been used as an alternative multilayer Bragg reflector. The proposed structure composed of prism/Au/porous GaN/(GaN/porous GaN) N/substrate. The numerical studies for the proposed structure are calculated using the transfer matrix method. The sensitivity, FoM, and Q-factor observed from this device are 3 × 104 nm/RIU, 6.6 × 104 RIU−1, and 9 × 108. This study records sensitivity 2875 times higher than the experimental study of a similar structure in other wavelength range. The proposed sensor can be used in biosensing applications because it records high local environment sensitivity.

In this work, we propose a heterostructure of different photonic crystal designs for multi passband filter applications at THz region. The suggested heterostructure is composed of regular photonic crystal (PC) designs and quasi-periodic photonic crystal (QPPC) of Fibonacci sequence. In our study, the QPPC is inserted between the two regular PC designs. By using the well-known transfer matrix method (TMM), we theoretically investigated the interaction of the incident electromagnetic waves with the proposed PC heterostructure. The numerical results demonstrate resonant peaks appeared in the transmittance spectrum of the proposed design. The tunability feature of the resonant peak is presented by controlling some of the design parameters such as the periodicity number of Fibonacci sequence value and the thickness of the constituent layers. In addition to that, we demonstrated the effect of the hydrostatic pressure on the resulted resonant peaks and the transmittivity of the proposed filter as well. The tunability feature of the resulted resonant peaks make our proposed filter act as multi passband filter via controlling the design parameters at the THz region.

In the present study, we have theoretically proposed a novel sensing tool based on a polymer defective one dimensional photonic crystal for highly accurate and sensitive pressure detection. The strain sensitive refractive indices of photonic crystals constituent materials have been considered to realize a pressure sensor device. The strain sensitive refractive index contrast is the main factor to achieve the goal. The numerical results satisfy significant changes in the refractive indices of these materials with applied hydrostatic pressure. Therefore, the sensitivity of the resonant mode that formed inside the photonic bandgap is very high to the pressure changes. Moreover, the optimization of the parameters of the one dimensional photonic crystals constituent materials such as the angle of incidence, number of layers and thickness of the defect polymer layer has been analyzed to investigate the most possible performance. By using an optimizing process, we have investigated a relatively high sensitivity of the proposed sensor that could reach 21.16 THz/GPa or 199.66 nm/GPa.

Rapid and sensitive detection of fat concentration in milk is a necessary part for citizens in each country. Bio-photonic sensing techniques are an accurate best way to detect biosensing measurements. The main aim of the proposed device is to make a more effective sensor to detect fat concentration in milk. A novel bio-photonic sensor based on the ternary photonic crystal of porous silicon is proposed. The key factor used here is that the dielectric constant of the milk depends strongly on the fat concentration. The proposed structures are (A) asymmetric ternary photonic crystal: (PSi1/PSi2/PSi3)(N)/Sample/(PSi1/PSi2/PSi3)(N) substrate, and (B) symmetric ternary photonic crystal: (PSi1/PSi2/PSi3)(N)/Sample/(PSi3/PSi2/ PSi1)(N) substrate. PSi and N denote to porous silicon layer and the number of layers, respectively. The numerical calculations for the proposed structure are calculated by using the transfer matrix method. Our biosensor is more efficient than some of the available sensors to sense the fat concentration in milk.

A defective one-dimensional photonic crystal is investigated as a biosensor to detect malaria disease. The proposed photonic structure is air/(GaN/Porous GaN)N/Sample/(GaN/Porous GaN)N/Substrate. The red blood cells sample of the human being is used as a sample defect in the proposed optical device. The pioneer transfer matrix method is used to analyze the transmittance spectra. A change in sample refractive index highly affects the transmittance resonant peak and this shift in the peak plays a key role in the operation of the device. The relatively high figure of merit of 1022 RIU−1 with a sensitivity of 1472 nm/RIU and quality factor of 1076 is detected. The proposed sensor is relatively better than others available to detect malaria disease.

In this work, we design a novel refractive index sensor in the terahertz region. The proposed structure is (PSi1/PSi2)N/Sample/Gyroidal Graphene/substrate. PSi1 and PSi2 are porous silicon with porosity of 80% and 30%, respectively. This sensor based on the Tamm plasmon polariton at the porous silicon interface of photonic bandgap and gyroidal graphene. The appearance of Tamm plasmon polariton at the interface is because of the plasmonic behavior of gyroidal graphene and the controlled porosity of silicon layers. Porous silicon is used due to its refractive index controllable by the porosity, pore size, and sample material filling pores. Tamm plasmon polariton is highly sensitive to the change in the refractive index of the sample material in the order of air index. The effects of the different variables such as gyroidal graphene volume fraction, sample index, the thickness of the gyroidal graphene layer, and the number of periods are studied. The optimizations are performed to improve the performance of the sensor. The high sensitivity of 18.6 THz/RIU is achieved with better FoM 126,835 RIU−1 and Q-factor 26,300. The investigated sensor using gyroidal graphene records performance more than quadrupled comparing with the same structure with graphene sheets. This sensor can be useful in several fields such as gas sensing, environmental monitoring, and biosensing.

In this paper, a novel refractive index sensor in terahertz region is proposed. The proposed structure is prism/(sample/porousTa2O5)15/sample/gyroid metal/substrate. The sensor is based on the Tamm plasmon polariton at the interface between porous one-dimensional photonic crystal and gyroidal metal. The gyroidal metal has been used as an alternative metal and its refraction index can be tuned by the gyroid parameters. The effects of the metal volume fraction and sample refractive index on the performance are studied to improve the ability of the sensor. The proposed sensor achieves high sensitivity of 6.7 THz/RIU, a high figure of merit 6*103 RIU−1, a high-quality factor of 3*103, and a low detection limit of 9*10−6 RIU. The proposed device can be a good candidate for fabricating gyroid metal and porous material-based biosensors, active optoelectronic and polaritonic devices.