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In this paper, a plasmonic filter is realized which consists of a T-shaped stub resonator and two side-coupled rectangular cavities; forming an inverted E-type structure connected to the main waveguide. Initially, the device is investigated for the function of a band stop filter in the telecommunication band. Later, the proposed device is investigated for bandpass filtering application by using Vanadium dioxide as an active material to show the improvement in transmittance, modulation depth, quality factor, and tunability of the device. Vanadium dioxide is filled into all four arms of the inverted E shaped structure. For the OFF-state, the electric field is applied to the T shape structure which are; arm 2 and arm 4 whereas for the ON-state, the electric field is applied to the two-side coupled rectangular cavities named as arm 1 and arm 3. The device has shown its potential application in high-quality factor filtering, switching, and modulation applications in telecommunication bands. The quality factor of 208 and 138.18 is achieved for ON-state and OFF-state respectively, whereas the quality factor is further increased and a high value of 308 is obtained by optimizing the device parameters. An extension ratio of modulation of 18.45 dB is attained which can be further increased to 19.95 dB by changing the width of the cavities. Device optimization is performed to show that the bandwidth and transmittance of the spectrum can be manipulated by changing the device parameters like width, length, and height of the cavities. Additionally, the effect of the Elasto-optic effect is also shown which results in a huge tunability of 650 nm and an increase in the modulation depth to 25.8 dB. The device has demonstrated its potential for use in filtering and switching for photonic integrated circuits. [ABSTRACT FROM AUTHOR]

Plasmonics is an emerging and very advantageous technology which provides high speed and tiny size devices for fulfilling the demand of today's high-speed world. SPPs are the information carrying elements in plasmonics, which are capable of breaking the diffraction limit. Plasmonics technology has shown its application in uncountable nanophotonic applications like switching, filtering, light modulation, sensing and in many more fields. Modulators are the key components of integrated photonic system. Various modulators which work on different effects are discussed in this study for providing a universal idea of modulators to researchers. Some useful plasmonic active materials are also discussed which are used in most of plasmonic modulators and other active devices. Previously, many researchers have worked on many kinds of modulators and switches, which operate on different kind of operating principles. For providing an overview about plasmonic modulators, their classification and their operation, we have discussed the state of art of some previously introduced modulators and switches which operates on electro-refractive effects and include electro-optic effect, Pockels effect, free charge carrier dispersion effect, phase change effect, elasto-optic effect, magneto-optic effect, and thermo-optic effect. Instead of different effects used in plasmonic switches and modulators different active materials like liquid crystals, graphene, vanadium di-oxide, chalcogenides, polymers, indium tin oxide, bismuth ferrite, barium titanate, and lithium niobate are also explained with their properties. Additionally, we also compared modulators based on different effects in terms of their design characteristics and performances. [ABSTRACT FROM AUTHOR]

This paper presents a plasmonic metamaterial sensor utilizing an I-shaped gold resonator. The sensor is simulated using the finite-element method (FEM) to detect gas and liquid (ethanol solutions) in the infrared wavelength range of 0.5–2.5 µm. The sensor structure consists of three layers, with a VO2 substrate sandwiched between a bottom SiO2 substrate and a top gold resonator. The design exhibits distinct absorption characteristics across the range of 0.5–2.5 µm, tailored for different gas and liquid sensing applications. A comparison is made between the two states of VO2 to investigate the sensitivity of the device. Geometrical parameters, including height and width, are optimized, and three types of comparisons are conducted. First, a sensitivity comparison is made between this work and previously published research. Second, a Quality factor and Figure of Merit comparison is performed. Finally, a sensitivity comparison is made between different sensing techniques and the technique employed in this work. After optimizing the design parameters, the device demonstrates the highest detection sensitivity for gas and ethanol solutions, yielding results of 2800 (nm/RIU) and 2600 (nm/RIU), respectively. The proposed I-shaped gold-based metamaterial exhibits the potential to be utilized as a lab-on-chip biosensor. [ABSTRACT FROM AUTHOR]