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Ifat Jahangir

Publications and source records attributed to Ifat Jahangir.

4 recordsLinked to original sources

Facile Algebraic Representation of a Novel Quaternary Logic

In this work, a novel quaternary algebra has been proposed that can be used to implement an arbitrary quaternary logic function in more than one systematic ways. The proposed logic has evolved from and is closely related to the Boolean algebra for binary domain; yet it does not lack the benefits of a higher-radix system. It offers seamless integration of the binary logic functions and expressions through a set of transforms and allows any binary logic simplification technique to be applied in quaternary domain. Since physical realization of the operators defined in this logic has recently been reported, it has become very important to have a well-defined algebra that will facilitate the algebraic manipulation of the novel quaternary logic and aid in designing various complex logic circuits. Therefore, based on our earlier works, here we describe the complete algebraic representation of this logic for the first time. The efficacy of the logic has been shown by designing and comparing several common logic circuits with existing designs in both binary and quaternary domain.

cs.AR

Negative Refraction with High Transmission in Graphene-hBN Hyper Crystal

In this article, we have theoretically investigated the performance of graphene-hexagonal Boron Nitride hyper crystals to demonstrate all angle negative refraction.Hexagonal Boron Nitride, the latest natural hyperbolic material; can be a very strong contender to form a hyper crystal with graphene due to its excellence as a graphene-compatible substrate. Although bare hexagonal Boron Nitride can exhibit negative refraction, the transmission is generally low due to its high reflective nature. On the other hand, due to two dimensional nature and metallic characteristics of graphene in the frequency range where hexagonal Boron Nitride behaves as a type-I hyperbolic Metamaterial, we have found that graphene-hexagonal Boron Nitride hyper-crystals exhibit all angle negative refraction with superior transmission. This has been possible because of the strong suppression of reflection from the hyper-crystal without any adverse effect on the negative refraction properties. This finding can prove very useful in applications such as superlensing, routing and imaging within a particular frequency range. We have also presented an effective medium description of the hyper crystal in the low k limit and validated the proposed theory using general transfer matrix method and also full wave simulation.

physics.optics

Ultrathin Ultra-broadband Electro-Absorption Modulator based on Few-layer Graphene based Anisotropic Metamaterial

In this article, a few-layered graphene-dielectric multilayer (metamaterial) electro-optic modulator has been proposed in the mid and far infrared range that works on electro-absorption mechanism. Graphene, both mono layer and few layer, is an actively tunable optical material that allows control of inter-band and intra-band transition by tuning its chemical potential. Utilizing this unique feature of graphene, we propose a multilayer graphene dielectric stack where few layer graphene is preferred over mono layer graphene. Although the total thickness of the stack still remains in the nanometer range, this device can exhibit superior performances in terms of (i) high modulation depth, (ii) ultra-broadband performance, (iii) ultra-low insertion loss due to inherent metamaterial properties, (iv) nanoscale footprint, (v) polarization independence and (vi) capability of being integrated to a silicon waveguide. Interestingly, these superior performances, achievable by using few layer graphene with carefully designed metamaterial, may not be possible with mono layer graphene. Our proposals have been validated by both the effective medium theory and general transfer matrix method.

physics.optics

On the Design and Analysis of Quaternary Serial and Parallel Adders

Optimization techniques for decreasing the time and area of adder circuits have been extensively studied for years mostly in binary logic system. In this paper, we provide the necessary equations required to design a full adder in quaternary logic system. We develop the equations for single-stage parallel adder which works as a carry look-ahead adder. We also provide the design of a logarithmic stage parallel adder which can compute the carries within log2(n) time delay for n qudits. At last, we compare the designs and finally propose a hybrid adder which combines the advantages of serial and parallel adder.

cs.AR