الفهرس 
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Abstract
• In this manuscript, the optical properties of a 1D-FQSNPCs design have been demonstrated by using the transfer matrix method. According to the analysis of optical fundamentals, we found that a PBG with a cutoff frequency characteristic appears in the terahertz region which can be tunable over this range. The tunability feature of the photonic bandgap and the cutoff frequency can be approached by some different parameters like the thickness of the superconductor material, the operating temperature, the nanocomposite material’s volume fraction, and finally angle of incidence. Also, it is found that one of the most affected parameters in the resulted PBG and the cutoff frequency is the change in the number of orders of Fibonacci sequences where the PBG becomes wider and sharper with increasing the Fibonacci orders. Also, we have examined the significance of the volume fraction of the nanocomposite material on the resulted optical properties where there are increase the absorption and also decrease in transmission. A lot of applications may be launched such as band-pass filters, high reflection mirrors, fibers, and microcavities. The TMM and MATLAB software both have been used to carry out the simulation pertaining to the work as in the following steps also.
• Novel designs of a 1DDSNPC biosensor have been investigated based on detecting malignancy in different samples of brain tissues. The cavity of proposed the 1DDSNPhC (AB)2CDC(AB)2 is composed of pair of nanocomposite SC buffer layers which are fabricated on either side of the cavity layer to strengthen the interaction between the light fluid sample under investigation. The performance of the proposed design has been evaluated by optimizing the sensitivity of the proposed design under the influence of various brain tissues. In this study, the sensitivity of the design has been improved by increasing the values of different parameters during fabrication such as the thickness of the cavity layer, and volume fraction of nanocomposite SC buffer layers. The optimized values of cavity layer thickness and volume fraction corresponding to which sensitivity is maximum with lymphoma and multi sclerosis brain tissue samples are 15dd and 0.8 respectively.
• Moreover, the present work only considers the external tunability due to changes in temperature as well as the angle of incidence. The tunability associated with internal parameters is beyond the scope of the present work. It allows tunability of the defect mode inside the PBG of our structure by means of a change in temperature of the ambient medium of the nanocomposite layer and the change in angle of incidence. The evaluation of the performance of the design has been conducted by calculating the (S), (FOM), (QF), and finally (LOD) parameters associated with the proposed work. The maximum sensitivity which can be achieved by the proposed design is 4139.24 nm/RIU corresponding to a sample containing a wall of brain tissues with cavity layer thickness 15dd and θ = 63° at T = 4.5 K. It can be marginally reduced between 4.12658 nm/RIU to 4.07594 nm/RIU by changing the temperature between 10 K to 90 K, respectively under the same sample, But the increase in the temperature improves the intensity of defect mode significantly which is one of the prime requisites in designing of any biosensor. Thus, the externally tunable bio-sensing capabilities of our design may play a significant and decisive role in the field of biomedical diagnosis. Finally, the findings of this work may be utilized for designing externally tunable biosensors composed of nanocomposite superconducting materials to monitor, detect, and sense different kinds of bio-fluids with ultra-enhanced sensitivity.