Invitation: MS Thesis Defense of Nahidul Shadin

Hello ME Community,
You are invited to join the Masters Thesis Defense of Nahidul Shadin, on Friday, April 24, beginning at 10:00am.  The defense will be presented in person in the Engineering Building room 210-I. (the Mechanical Engineering Conference room)

Advisor: Dr. Alok Ghanekar

Title: Reversible Symmetry Breaking of Tunable Directional Thermal Emission in VO2-SRO Gratings

Abstract:
Thermal radiation from naturally occurring materials is inherently incoherent, broadband, and diffuse. The ability to control the directional and spectral properties of thermal emission is of fundamental importance for applications in sensing, radiative cooling, energy harvesting, and long-wave infrared communications. In recent years, metamaterials and metasurfaces have enabled the creation of coherent, directional, and narrowband thermal radiation through subwavelength structuring. However, most demonstrated thermal emitters exhibit static, angular symmetric responses, limiting their functionality. This thesis presents a numerical investigation of a tunable, angular-asymmetric thermal emitter based on a metal insulator-metal (MIM) resonance grating incorporating vanadium dioxide (VO2) as a phase-change material. The proposed structure employs an asymmetric dielectric substrate of GaAs with strontium ruthenate (SRO) and VO2 gratings situated over a gold reflector, which enables dynamic switching between symmetric and asymmetric emission states. The design exploits guided-mode resonances and diffraction in the mid-wave infrared regime (8–13 μm) to achieve angular asymmetric absorption and emission.