The Mid-IR Photonics Lab, led by Dan Wasserman at the Microelectronics Research Center, has demonstrated a novel tunable optical cavity using the ferroelectric material barium titanate (BTO).
Working with Alexander Demkov’s Group in UT Physics and La Luce Cristallina Inc., graduate student Daniel Krueger recently published "Compact 1D tunable barium titanate waveguide cavity," in Optica.
Krueger used an inverse design technique to fabricate high reflectivity mirrors in a 1D BTO waveguide, and then used these mirrors to form a 1D resonator. He was able to show cavity quality factors of ~3000, and moreover, that when a bias is applied to the BTO, the change in refractive index of the electro-optic material can tune the 1D cavity modes to fully modulate optical transmission through the waveguides.
This work is another step towards developing low-power, high-speed, and reconfigurable photonic circuitry in BTO. Published in Optics Letters, with coauthors Zarko Sakotic, Liang Tian, Amogh Raju, Hee Gon Kim and Divya Hungund of the Wasserman Group, and Dr. Agham Posadas (La Luce Cristallina) and Prof. Alexander Demkov (UT Physics). This work was funded by AFOSR, ONR, and NASA.