Refractive Index Sensor Based on Surface Plasmon Resonance Excitation in a D-Shaped Photonic Crystal Fiber Coated by Titanium Nitride

Overview of Recent Advances in the Design of Plasmonic Fiber-Optic Biosensors

“…In 2020, Monfared [21] reported a D-shaped PCF-based plasmonic biosensor using titanium nitride as an alternative plasmonic material (plasmonic nanofilm) with a RI detection range of 1.44 to 1.52 and two linear sensing regions with an average spectral sensitivity of −16,275 nm/RIU for analyte RI ranging from 1.44 to 1.48, and −7571 nm/RIU for analyte RI between 1.485 and 1.52, respectively [21]. While the detection range of this biosensor was more limited comparing to [37], the main advantages of this biosensor were utilizing a cost-effective material (titanium nitride) instead of gold, and also showing a higher sensitivity and figure of merit comparing to gold-based D-shaped PCF biosensors.…”

“…Prism-based SPR sensors are widely used in chemical and biological applications for real-time detection of unknown analytes as highly accurate biosensors [19,20]. However, the most important problem associated with the use of prism-based SPR sensors is bulkiness of the setup, which significantly reduces its applicability in in-situ biosensing, especially biosensing in hard-to-reach locations [18,21]. However, the intersection of plasmonics (SPR sensors) and fiber-optics provide exciting opportunities for scientists working in the fields of biology, chemistry, and medicine to realize SPR sensors in a miniaturized structure [18,21].…”

“…However, the most important problem associated with the use of prism-based SPR sensors is bulkiness of the setup, which significantly reduces its applicability in in-situ biosensing, especially biosensing in hard-to-reach locations [18,21]. However, the intersection of plasmonics (SPR sensors) and fiber-optics provide exciting opportunities for scientists working in the fields of biology, chemistry, and medicine to realize SPR sensors in a miniaturized structure [18,21]. This miniaturized structures not only can reduce the size of sensor significantly, but also can offer far more flexibility in terms of the design, materials, and sensing performances of the device.…”

“…Plasmonic fiber-optic sensors can solve inherent issues of conventional SPR sensors and add potential new characteristics such as harsh environment tolerance, remote sensing, and distributed sensing to such sensors [18,21]. In recent years, several fiber optic plasmonic biosensing configurations are proposed to detect biological samples and molecules.…”

“…As different metals can induce different plasmonic properties, optical fibers with different plasmonic materials have also been studied in recent years. While noble metals including gold (Au) and silver (Ag) nanofilms and nanoparticles (NPs) are dominant plasmonic materials in these studies, the field is now experience a rise of alternative plasmonic materials [22] in the design of fiber-optic biosensors such as transition metal nitrides [21], graphene [23], and transition metal oxides [24]. In this review paper, the new advances in the field of plasmonic fiber-optic biosensors, in particular new design concepts and materials, will be discussed in detail.…”