Coherent perfect absorption in metal-dielectric composites: Theory and recent application

Title : Coherent perfect absorption in metal-dielectric composites: Theory and recent application

Abstract:

This work explores coherent perfect absorption (CPA) in metal-dielectric composite medium (CM) under bidirectional illumination (plane waves or Gaussian beams). CPA conditions are derived for normal and oblique incidences. It is observed that broad beams enable CPA through paraxial approximation, while narrower beams exhibit slight imperfections. The CPA dependence parameters are beam waist, angle of incidence, and medium properties.

We derive a simple function to determine CPA in a medium based on electromagnetic (EM) wave analysis and EM boundary conditions for TE polarised light. This expression can estimate all the necessary parameters required for CPA and the result exactly matches with numerical simulations.

Furthermore, a scheme for high-precision position sensing uses a three-CM slab, where the wavelength of CPA is sensitive to the position of the middle layer. The periodic occurrence of CPA resonances across various positions and wavelengths highlights its potential for precise sensing applications.

Biography:

Dr. Sanjeeb Dey is working as an assistant professor at Ramakrishna Mission Vidyamandira in Computer Science and Electronics Department. He graduated from Banaras Hindu University (BHU) and got a doctoral degree (Ph. D.) from the University of Hyderabad (UOH) in 2017. He just set up his lab to work on quantum optics in the vicinity of theoretical research, which is actively involved in light-matter interaction, plasmonics in the waveguide, nonlinear optics, meta-materials, etc. in the single or stratified medium.