arXiv subjects

Tulika Agrawal

Publications and source records attributed to Tulika Agrawal.

3 recordsLinked to original sources

arXiv2026

Influence of metal nanoparticles on whispering gallery modes of a microcavity

Photonic microcavities offer high energy density and low mode volume and attract special attention due to wide range of applications. Subsequent developments in the area of plasmonic nanocavities have also opened up applications despite their high absorptive properties. In the last two decades, photonic-plasmonic hybrid microcavities have been investigated extensively. In this article, we have conducted a review of the literature on photonic and plasmonic systems individually as well as in hybrid systems. Along with the underlying physics, applications such as cavity quantum electrodynamics, lasing, sensing, nonlinear optics and Raman spectroscopy have been reviewed. The outputs of the systems for each applications have been discussed and compared for photonic and hybrid systems. This review will provide a thorough understanding of the effects of optical cavities and plasmonics and their applications.

physics.optics↗

arXiv2016

Secure Analog Network Coding in Layered Networks

We consider a class of Gaussian layered networks where a source communicates with a destination through $L$ intermediate relay layers with $N$ nodes in each layer in the presence of a single eavesdropper which can overhear the transmissions of the nodes in any one layer. The problem of maximum secrecy rate achievable with analog network coding for a unicast communication over such layered wireless relay networks with directed links is considered. A relay node performing analog network coding scales and forwards the signals received at its input. The key contribution of this work is a lemma that provides the globally optimal set of scaling factors for the nodes that maximizes the end-to-end secrecy rate for a class of layered networks. We also show that in the high-SNR regime, ANC achieves secrecy rates within a constant gap of the cutset upper bound on the secrecy capacity. To the best of our knowledge, this work offers the first characterization of the performance of secure ANC in multi-layered networks in the presence of an eavesdropper.

cs.IT↗

arXiv2016

Network Simplification for Secure AF Relaying

We consider a class of Gaussian layered networks where a source communicates with a destination through L intermediate relay layers with N nodes in each layer in the presence of a single eavesdropper which can overhear the transmissions of the nodes in the last layer. For such networks we address the question: what fraction of maximum secure achievable rate can be maintained if only a fraction of available relay nodes are used in each layer? In particular, we provide upper bounds on additive and multiplicative gaps between the optimal secure AF when all N relays in each layer are used and when only k, 1 <= k < N, relays are used in each layer. We show that asymptotically (in source power), the additive gap increases at most logarithmically with ratio N/k and L, and the corresponding multiplicative gap increases at most quadratically with ratio N/k and L. To the best of our knowledge, this work offers the first characterization of the performance of network simplification in layered amplify-and-forward relay networks in the presence of an eavesdropper.

cs.IT↗