V. Subramanian

Bio: V. Subramanian is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topic(s): Metamaterial & Electromagnetic radiation. The author has an hindex of 1, co-authored 1 publication(s) receiving 3 citation(s).

Directional cloak formed by photonic crystal waveguides

Abstract: A method to cloak larger dimensional scattering objects against normal incident linearly polarized microwave is reported in this work. The cloaking device utilizes the principle of photonic crystal wave guiding mechanisms that mould and steer the wave path smoothly around the scattering objects. The proposed method is scalable at all length-scales from cm to nm band frequencies. This approach may be employed for the development of microwave photonic components that are aimed for independent and simultaneous electromagnetic wave operations.

Spatial Beam Compression and Effective Beam Injection Using Triangular Gradient Index Profile Photonic Crystals

Abstract: Spatial beam compression of an electromagnetic wave is one of the fundamental techniques employed in microwaves and optics. As there are many ways to achieve this task using the combination of prisms and lenses, recent research suggests the parabolic gradient index photonic crystals (GRIN PC) for the design of spatial beam compressor owing to its functionalities. However, the fabrication of a graded media with the parabolic proflle is a di-cult challenge in practical realization. As an alternative, present work attempts this problem with respect to the triangular gradient index proflle. The performance and aspects of the beam compression are investigated experimentally using the pillar type GRIN PC at the microwave length-scales. The utility of the device for an efiective beam injection to the photonic-waveguide component is further demonstrated experimentally.

Directional Cloaking by Quadruple Luneburg Lens System

Abstract: In this study, we propose a method based on graded-index medium in order to cloak scatterer objects. We use discretized Luneburg lenses as a graded-index medium and the proposed structure consists of four discretized Luneburg lenses, i.e., it is can be considered as a quadruple Luneburg lens system. Numerical investigations for directional cloaking are performed by using finite-difference time-domain methods. It is shown that an object can be cloaked inside the dark zone of created by Luneburg lenses and the proposed structure can provide cloaking at optical wavelengths.

All-angle polarization insensitive cloaking in 2D photonic crystals

Abstract: In this article, a 2D hole-type square lattice photonic crystal is considered to achieve all-angle polarization insensitive cloaking using self-collimation phenomenon. The regarded structure is composed of air holes in a high dielectric background of PbTe (nPbTe˜6) and is applicable for Mid-IR range. The bandwidth achieved for the maximum deviation angle of self-collimation of 2o is Δω/ωc=0.55% corresponding to Δλ=22.6nm at central wavelength of λc=4.1175μm. The presented structure is capable of cloaking of any structure in any size and shape since the propagating wave is not interacting with the cloaking region. To reduce the reflections from interfaces an optimized one-layer antireflection has been designed to reduce the reflections caused due to index mismatch. The structure and its functionality have been investigated by the PWE and the FDTD methods.