IDR @ IIT Bhubaneswar
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Item Microfiber Assisted Highly Birefringent PCF-Based Interferometric Sensors(2017) Dash J.N.; Dass S.; Jha R.We propose a highly sensitive interferometric sensor based on a tapered fiber concatenated with a highly birefringent (HiBi) photonic crystal fiber (PCF) for the detection of physical as well as chemical parameters. The splicing of single mode fiber (SMF) and HiBi PCF is achieved without any offset. The tapered section is employed for curvature and temperature sensing while the HiBi PCF is used for refractive index sensing. Experimental results show that the proposed Mach-Zehnder interferometer has a curvature sensitivity of 14.77 nm/m-1 with a resolution of 6.77 10-4m-1. Furthermore, the refractive index (RI) sensitivity is found to be 257 nm/RIU along with a resolution of 3�10-5 RIU, which is comparable to commercial refractometer. The proposed setup shows a temperature sensitivity of 311 pm/�C. The curvature, RI, and temperature sensitivity are significantly higher with linear response. � 2016 IEEE.Item Ultrasensitive THz - Plasmonics gaseous sensor using doped graphene(2016) Purkayastha A.; Srivastava T.; Jha R.We propose a surface plasmon resonance (SPR) based gas sensor in terahertz frequency with Otto configuration based on attenuated total reflection (ATR) technique using free standing doped graphene monolayer. Angular interrogation method has been used to study the performance of the sensor in terms of sensitivity and detection accuracy. Different chemical potential of graphene monolayer has been investigated to study its effect on these performance parameters. The results show that the optimization of the gap distance between the prism base and the graphene monolayer has significant effect on the reflectivity of SPR sensing. This SPR based gas sensor shows ultrahigh sensitivity of 34.11 deg/RIU along with an ultrahigh Figure of Merit (FOM) of more than 1150 RIU-1. � 2015 Elsevier B.V. All rights reserved.Item Highly Sensitive Side-Polished Birefringent PCF-Based SPR Sensor in near IR(2016) Dash J.N.; Jha R.We propose a highly sensitive side-polished birefringent photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR). The polished surface of the proposed structure is coated with indium tin oxide (ITO) to excite plasmon and the analytes can be placed on the flat surface easily instead of filling the voids. The birefringent nature of the structure helps in coupling more fields to the ITO-dielectric interface. With the optimum thickness of 110�nm of ITO, the structure shows a maximum wavelength sensitivity of 17000�nm/RIU with a resolution of 5.8 � 10?6�RIU. Further this also showed an amplitude sensitivity of 74�RIU?1 along with a resolution of 1.35 � 10?5�RIU. Moreover, the effect of bending on this low loss structure is also analyzed. � 2016, Springer Science+Business Media New York.Item On the Performance of Graphene-Based D-Shaped Photonic Crystal Fibre Biosensor Using Surface Plasmon Resonance(2015) Dash J.N.; Jha R.We propose a D-shaped photonic crystal fibre-based surface plasmon resonance sensor considering graphene on silver for sensing of refractive index of analyte and thickness of biolayer. The different structural and material parameters associated with sensor have been optimised. Graphene not only helps in adsorption of biomolecules due to ?-? stacking interaction but at the same time prevents oxidation of metal-like silver. Numerical simulation shows that amplitude sensitivity of the proposed structure for chemical analytes is 216�RIU?1 (refractive index unit) with a resolution of 4.6 � 10?5�RIU while the wavelength sensitivity of the proposed sensor is found to be as high as 3700�nm�RIU?1 with resolution of 2.7 � 10?5�RIU. Further, the proposed sensor can also be used for the detection of biolayer thickness in both amplitude and wavelength interrogations. An amplitude sensitivity of 0.26�nm?1 with resolution of 39�pm and wavelength sensitivity of 2�nm�nm?1 with resolution of 50�pm is achievable for the determination of biolayer thickness. The proposed structure is easy to use as there is no need of filling of voids, and the analytes can be placed easily on the flat surface of photonic crystal fibre (PCF). � 2015, Springer Science+Business Media New York.Item Sensitivity enhancement by air mediated graphene multilayer based surface plasmon resonance biosensor for near infrared(2014) Maharana P.K.; Jha R.; Palei S.Air mediated surface plasmon resonance sensor at near infrared frequency for sensitivity enhancement has been proposed. The proposed sensor utilizes the advantage of air gap between chalcogenide prism and gold film and high adsorption efficiency of graphene for enhancement of sensitivity. The thickness of air and gold film has been optimized for multiple wavelengths. Based on angular interrogation, the sensitivity of the proposed sensor can be tuned by changing the wavelength of operation in near IR and by judiciously selecting number of graphene layer. The sensitivity of the proposed sensor is 43.18 /RIU for 10 graphene layer at 700 nm where as at 1000 nm, the sensitivity is 36.14 /RIU for same number of graphene layer. We found that the sensitivity of the sensor increases linearly with sensing layer refractive index and number of graphene layer at a given wavelength. Also, we found that the detection accuracy of the proposed sensor in near IR increases by more than 290% for L = 10 as compared to conventional SPR sensor. We believe that the proposed sensor could potentially open a new possibility for high performance SPR sensing. � 2013 Elsevier B.V. All rights reserved.Item On the Performance of Highly Sensitive and Accurate Graphene-on-Aluminum and Silicon-Based SPR Biosensor for Visible and Near Infrared(2014) Maharana P.K.; Srivastava T.; Jha R.We demonstrate the numerical analysis of surface plasmon resonance biosensor based on graphene on aluminum and silicon. Employing matrix method, it is found that the proposed sensor exhibits high imaging sensitivity ?400 RIU?1 to 550 RIU?1 in a large dynamic range from visible to near IR region. It is observed that the application of monolayer or bilayer graphene over aluminum not only protects it from oxidation but also enhances the adsorption of biomolecules, which results in the detection of large refractive indices ranging from aqueous solution to biomolecules (refractive index 1.330 to 1.480) with overall high performance in terms of imaging sensitivity and detection accuracy. � 2014, Springer Science+Business Media New York.Item Chalcogenide prism and graphene multilayer based surface plasmon resonance affinity biosensor for high performance(2012) Maharana P.K.; Jha R.Surface plasmon resonance based affinity biosensor comprising of 2S2G (Ge 20Ga 5Sb 10S 65) chalcogenide prism, graphene-multilayer and gold as a plasmon active metal is proposed for sensing over a broad wavelength range in visible and near infrared regime. We have investigated and carried out detailed analysis to design high performance affinity biosensor by exploiting the unique optical properties of chalcogenide glass and graphene. The performance of the biosensor has been quantified in terms of sensitivity and detection accuracy. The sensitivity of proposed biosensor increases significantly due to the presence of graphene where as the detection accuracy increases by more than 100% because of high index chalcogenide glass as compared to silica glass. Also, the detection accuracy of the proposed sensor in near IR is 16 times more as compared to that in visible. Adequate values of crucial design parameters have been optimized to achieve the best possible sensing performance over a broad wavelength range. � 2012 Elsevier B.V. All rights reserved.Item Design considerations for plasmonic-excitation based optical detection of liquid and gas media in infrared(2011) Jha R.; Sharma A.K.Surface plasmon resonance (SPR) sensor schemes based on silicon (Si) and chalcogenide glass are evaluated and compared for chemical as well as gas detection in a wide range of infrared (IR) wavelengths. The plasmonic characteristics in IR are critically dependent on the dispersive behavior of the coupling substrate material. The performance of sensor has been evaluated in terms of its intrinsic sensitivity (IS) that includes the FWHM and angular shift of SPR curve for a given change in refractive index of sensing medium. Both these materials are potential candidates for opening up new routes for detection in near- and mid-IR due to their strong dispersion capabilities as compared to normal silica-based glass. The IS of chalcogenide glass-based SPR sensor is found to be larger than Si-based one for a broad wavelength range of 700-2500 nm indicating that chalcogenide glass-based probe provides more sensitive as well as accurate sensing procedure than Si-based probe. Further, for both glasses, the single probe can be used for both aqueous as well as gaseous sensing. Furthermore, for both glasses, it is found that the values of IS are much larger for gaseous sensing in comparison to liquid sensing. � 2010 Elsevier B.V.Item Sensitivity enhancement of a surface plasmon resonance based biomolecules sensor using graphene and silicon layers(2011) Verma R.; Gupta B.D.; Jha R.A surface plasmon resonance based biomolecules sensor using silicon and graphene layers coated over the base of the high index prism sputtered with gold has been analyzed. The graphene layer has been used to enhance the adsorption of biomolecules while the addition of silicon layer between gold and graphene increases the sensitivity. The thicknesses of gold and silicon layers along with the number of graphene layers have been optimized to achieve the best performance of the sensor in terms of sensitivity and Full Width at Half Maximum (FWHM). To see the effect of wavelength of the light source, simulations have been carried out for three different wavelengths. The best performance is obtained for 633 nm wavelength with optimized thicknesses of gold and silicon layers as 40 nm and 7 nm respectively while the optimum number of graphene layers is 2. The sensitivity obtained with optimized parameters and additional silicon layer, is more than twice the value reported in the literature. � 2011 Elsevier B.V. All rights reserved.