Efficient way for detection of alcohols using hollow core photonic crystal fiber sensor

Design of a Highly Sensitive Photonic Crystal Fiber Sensor for Sulfuric Acid Detection

“…When the EM wave travels through the core and interacts with the sample inside the core, a fraction of light trapped by the air holes surrounds the core. This type of loss is called the confinement loss and it occurs in every type of optical waveguide and is calculated by using the following expression [ 14 , 15 , 18 ]: where λ stands for the operating wavelength and Im( n eff ) is the imaginary part of the effective refractive index. The relationship between the confinement loss and the propagating EM waves is shown in Figure 5 .…”

“…Finally, fused silica was selected as the base material of the proposed sensor due to its supreme advantages over other materials in the optical domain. The light-dependent refractive index (RI) of the background material is calculated using the Sellmier equations as follows [ 14 ]: …”

“…Although all types of PCFs can be effectively employed in communication applications, only porous core and hollow-core PCFs can be employed in sensing and spectroscopic applications. Hitherto, several optical fiber-based gas and liquid sensors have been proposed to operate in the terahertz [ 9 , 10 , 11 , 12 , 13 ] or visible optical regimes [ 14 , 15 ]. The optical sensors that operate on terahertz signals offer higher sensitivity [ 16 , 17 ].…”

“…Researchers have proposed using a constant refractive index through all terahertz bands, which is impractical. On the other hand, some authors proposed optical sensors where the wavelength-dependent refractive index of the analyte was considered, which ensures better reliability [ 14 ]. In that article, the authors proposed a hollow-core PCF-based alcohol sensor that offered high relative sensitivity of 89%, with negligible confinement loss at an operating wavelength of 1.55 µm.…”

“…However, in the last few years, several optical fiber-based chemical sensors were proposed based on the same principle (spectroscopy) used in Ref. [ 14 ]. Researchers recently introduced different metal-coated plasmonic sensors, ensuring excellent sensing characteristics [ 18 , 19 , 20 , 21 , 22 ].…”