Design Optimization and Fabrication of Graphene/J-Aggregate Kretschmann-Raether Devices for Refractive Index Sensing Using Plasmon-Induced Transparency Phenomena

Plasmonics - Here, a novel plasmon-induced transparency (PIT) sensing platform based on a Kretschmann–Raether configuration with graphene/J-aggregate materials is proposed. The J-aggregate...     

In Search of Engineered Prokaryotic Chlorophyllases: A Bioinformatics Approach

Chlorophyllase (Chlase) is considered as the first and most important enzyme in chlorophyll degradation pathway. Although there is abundant information regarding plant Chlases and their biological functions, comparatively little is known about their prokaryotic counterparts. In the present study, we employed several bioinformatics tools to assess the phylogenetic relationships in bacterial and cyanobacterial Chlases as well as predicting their molecular and physicochemical properties. The phylogenetic tree analysis classified the bacterial and cyanobacterial chlorophyllases into three distinct clades. All bacterial and cyanobacterial chlorophyllases possessed at least one alpha/ beta hydrolase family domain (pfam12695). Cyanobacterial chlorophyllases pI analysis indicated that they generally have acidic pH, while the pI of bacterial chlorophyllases ranged from acidic (4.58) to highly basic (10.78). Cyanobacterial chlorophyllases generally contained 1 disulfide bond, while bacterial chlorophyllases averagely contained 3 disulfide bonds. Interestingly, while cyanobacterial chlorophyllases contained one or two N-glycosylation sites, bacterial chlorophyllases contained higher numbers of N-glycosylation sites (6 and 7). The findings of the present study would be useful in paving the road for sophisticated engineering of prokaryotic chlorophyllases for biotechnological applications. It was also exhibited that catalytic triad (serine, glutamate or aspartate and histidine) is a critical factor for chlorophyllase activity.     

Steering of Guided Light with Graphene Metasurface for Refractive Index Sensing with High Figure of Merits

The steering of guided light in surface plasmon resonance (SPR) sensing platforms introduced more than eight decades ago from the first proposed optical sensor in 1983. However, sensing the environmental variation considering transverse modes is still require the attention from the scientist. Here, for the first time, by considering steering of guided light a high-performance SPR sensor base on Otto structure is proposed. By incorporating the graphene and white graphene in to a prism-waveguide configuration, we calculated the excitation of both TE(TM) modes as refractive index is changed from 1 to 1.04. to analysis of the structure finite-difference time-domain (FDTD) is applied. To benchmark of the structure performance parameters including sensitivity, figure of merit, polarization extinction ratio (PER), and insertion loss (IL) are calculated. Numerical results show that maximum sensitivity and figure of merit are obtained for TM modes of 1226 and 27 respectively. In such a case, graphene monolayer is applied. By considering coupling condition, at the μc?=?0.4 eV, the maximum value of PER is 75 dB, and IL is 0.022 dB. Moreover, it is obtained that in all these conditions PER is higher than 8 dB, and IL is less than 0.04 dB.

     

Black Phosphorous-Based Nanostructures for Refractive Index Sensing with High Figure of Merit in the Mid-infrared

Plasmonics - Two-dimensional materials have emerged as new type of smart materials that may impact advanced photonic devices. Here, to increase the light absorption, a black phosphorus-based...     

Design and Simulation of a Novel Tunable Terahertz Biosensor Based on Metamaterials for Simultaneous Monitoring of Blood and Urine Components

In this essay, a tunable metamaterial-based biosensor is proposed for simultaneous monitoring of blood components including cells, plasma, water, thrombus, and urine components as well as glucose, albumin, and urea. The proposed biosensor is based on optical sensors, and it provides real-time, label-free, and direct detection, small size, and cost-effectiveness that can be an alternative tool to other conventional methods. The influence of operating frequency, sample thickness, temperature, and radiation angle on the performance of the sensor is investigated by the finite element method (FEM). Numerical results show that the maximum sensitivity and figure of merit (FoM) in the high frequency are 500 (nm/RIU) and 2000, and for low frequency are 136 (µm/RIU) and 155, respectively. The footprint of the structure is 0.34 µm2, which is remarkably smaller than the other reported biosensing structures. The proposed biosensor has the potential to provide high sensitivity, high FoM, and a wide operating range for biomedical applications.

     

Analytical and Numerical Models of a Highly Sensitive MDM Plasmonic Nano-structure in Near-infrared Range

Plasmonics - Plasmon-induced transparency (PIT) is a spotlight technique for environmental monitoring. In this regard, a highly sensitive and tunable multilayer sensor including...     

SiO2–Silver Metasurface Architectures for Ultrasensitive and Tunable Plasmonic Biosensing

Plasmonics - Here, we indicate that metasurface-based biosensors consisting of silver-metasurface with SiO2 and working in the near-infrared (NIR) spectral range can obtain simultaneous...     

Fabrication Friendly Plasmonic Metasurface Sensing and Switching Configuration Based on Plasmonic Induced Absorption: Analytical and Numerical Evaluation

Plasmonics - Optical sensing and switching characteristic for a novel plasmonic metasurface structure are verified based on numerical and analytical evaluations for the proposed structure formed by...