A review on various sensing prospects of SPR based photonic crystal fibers

This review article deals with various prospects of the Photonic Crystal Fiber (PCF) and its applications in biosensing, refractive index (RI) sensing, biomedical imaging, dispersion compensation, supercontinuum and solitons generation. The gradual progress in PCF technology not only explored its application in optical communication but also extended to its effective utilization in PCF-based sensors. PCF is extensively used as a research object in order to curb the positive dispersion by changing either its cladding or core structure. Some existing works also focused on obtaining high nonlinearity in the PCF structures since high nonlinear PCF is used to direct the light in the fiber core only so that light can travel a larger distance without any alteration. But, nowadays, the modern era of optical fiber technology has been more inclined towards PCF-based surface plasmon resonance (SPR) biosensors or RI sensors. The functional mechanism of a biosensor relies on SPR which involves fiber integrated with plasmonic metals (i.e. gold, silver, copper, etc.) as these metals are responsible for the sensitivity of a biosensor. But, the major drawback of plasmonic metals is that they exhibit poor biomolecule adsorption. Therefore, this review mainly explores the possible way such as the incorporation of 2D/TMD materials (i.e. graphene, MoS2, etc.) to increase biomolecule adsorption. These materials play an important role to increase the sensitivity of a biosensor. Hence, metal/2D/TMD based combined heterostructure opens a suitable study window in the field of SPR biosensing that finds its application in cholesterol detection, cancer cell detection, DNA detection, protein and glucose sensing.