Phonon Light Switches: Leveraging Vibrations to Create Actively Tunable IR Devices

Topic: 
Phonon Light Switches: Leveraging Vibrations to Create Actively Tunable IR Devices
Thursday, February 25, 2021 - 1:30pm
Speaker: 
Thomas Beechem (Sandia National Laboratories)
Abstract / Description: 

Light possesses a wave nature. Phonons do too. Within the infrared portion of the spectrum, these waves have comparable energies leading to their interaction. Here, the interaction is leveraged to create tunable infrared filters that control transmission and reflection with no moving parts at the "push of a button" for applications in next generation imaging and on-chip spectroscopy. Practically, waferscale tunable infrared filters are first demonstrated by altering graphene's plasmonic dispersion using the dielectrics surrounding it resulting in gate-tunable variations (V < 10V) of reflectance by over 1 μm. These same filters are then integrated directly atop a broadband infrared detector in a proof-of-principle demonstration of a dynamically tunable pixel. Second, field induced changes in the phonons energies of lead zirconate titante (PZT) ferroelectric bilayers result in a tunable IR filter possessing high speed, latchable operation, and scalable fabrication. Taken together, the case studies highlight the utility of harnessing phonons to sculpt the spectral response of IR elements.

Bio: Thomas Beechem is a scientist affiliated with both the Applied Optical and Plasma Sciences Department and the Center for Integrated Nanotechnologies (CINT) at Sandia National Laboratories in Albuquerque, NM where he has served since obtaining his doctorate from the Georgia Institute of Technology in 2008. In this role, Thomas leads efforts focused on elucidating, and then leveraging, vibrational physics and the material responses of low-dimensional systems to enable next generation optical devices, power electronics, and spectroscopic methods. He has authored over 80 archival publications, holds 6 patents, and had his work selected as the featured "cover article" on 5 separate occasions by 6 different periodicals. He received a 2015 Defense Program Award of Excellence and was named one of Sandia's "Up and Coming Innovators" in 2016. In 2017, he was named an associate editor of the Journal of Heat Transfer.