DISSERTATION DEFENSE
Joseph Matson, Interdisciplinary Materials Science
*under the direction of Dr. Josh Caldwell
“Gaining Nanophotonic Control through Crystalline Anisotropy”
12.05.22 | 3:00pm CST | 048 Engineering Science Building | Zoom
Infrared (IR) optics form the basis for many important applications, including chemical spectroscopy for pharmaceuticals, medical testing, environmental monitoring, automotives, and aerospace, to name a few. However, current state of the art IR devices are plagued by bulky components, low efficiency, and low robustness. In response, IR nanophotonics have garnered strong interest for next generation devices. The most promising approaches for IR nanophotonics involve coupling light to free carriers in metals and doped semiconductors (plasmon polaritons), or to lattice vibrations of polar crystals (phonon polaritons). Plasmon polaritons offer broad tunability with low efficiency, and phonon polaritons offer high efficiency with low tunability. The work presented here focuses on phonon polaritons in low symmetry crystals, which have been shown to offer remarkable control over the confinement and propagation of light at scales much smaller than the optical wavelengths. In particular, we study the phonon polaritons of uniaxial, biaxial, and monoclinic systems – demonstrating ultrafast control, refractive polariton optics, tunable beam-steering, and broken symmetry propagation in natural crystals. We also explore the design of phonon energies through atomic-scale structuring of superlattices – stacks of alternating crystal layers. The results provide promising new paths for IR nanophotonic devices.