Joint OSE and ECE Departmental Seminar By Dr. Francesca Cavallo on Self-Assembled Metal Helices for Millimeter-through-THz Traveling Wave Tube Amplifiers

Departmental News

Alhassan Ahmed  Wins

Posted: October 1, 2021

Departmental News

Posted: October 1, 2021

Date: Friday, October 1, 2021 

Time:  at 3 PM 

Location:  Woodward Hall, Room 147


I will present a transformative route to obtain mass-producible helical slow-wave structures for operation in beam-wave interaction devices at millimeter-through-THz frequencies. The approach relies on guided self-assembly of conductive nanomembranes. The work coordinates simulations of cold helices (i.e., helices with no electron beam) and hot helices (i.e., helices that interact with an electron beam). The theoretical study determines electromagnetic fields, current distributions, and beam-wave interaction in a parameter space that has not been explored before.  These parameters include microscale diameter, pitch, tape width, and nanoscale surface finish. Informed by the simulation results, we design and fabricate prototype helices for operation as slow-wave structures at millimeter-through-THz frequencies, using metal nanomembranes. The nanomembrane stiffness and built-in stress control the diameter of the helices. The in-plane geometry of the nanomembrane determines the pitch, the chirality, and the formation of single vs. intertwined double helices..


Dr. Francesca Cavallo is an assistant professor at the Center for High Technology Materials and ECE department at the University of New Mexico.  Her research focuses on synthesis, assembly, fundamental properties and applications of inorganic sheets. Dr. Cavallo has twenty years of experience in nanoscale materials science and technology with complementary capabilities in electronics, optoelectronics, and electromagnetics. Her expertise spans nanosheets synthesis and processing,  nanostructured origami, strain-engineering, electrical-transport phenomena in multi-carrier systems, THz devices, and light-matter interactions. Dr. Cavallo has co-authored over 60 peer-reviewed publications, 7 patents, 4 patent applications, and numerous conference abstracts and proceedings.