Abstract
Merging the properties of VO2 and van der Waals (vdW) materials has given rise to novel tunable photonic devices. Despite recent studies on the effect of the phase change of VO2 on tuning near-field optical response of phonon polaritons in the infrared range, active tuning of optical phonons (OPhs) using far-field techniques has been scarce. Here, we investigate the tunability of OPhs of α-MoO3 in a multilayer structure with VO2. Our experiments show the frequency and intensity tuning of 2 cm-1 and 11% for OPhs in the [100] direction and 2 cm-1 and 28% for OPhs in the [010] crystal direction of α-MoO3. Using the effective medium theory and dielectric models of each layer, we verify these findings with simulations. We then use loss tangent analysis and remove the effect of the substrate to understand the origin of these spectral characteristics. We expect that these findings will assist in intelligently designing tunable photonic devices for infrared applications, such as tunable camouflage and radiative cooling devices.
Original language | English (US) |
---|---|
Pages (from-to) | 48981-48987 |
Number of pages | 7 |
Journal | ACS Applied Materials and Interfaces |
Volume | 13 |
Issue number | 41 |
DOIs | |
State | Published - Oct 20 2021 |
Funding
K.A. acknowledges the support from the Office of Naval Research Young Investigator Program (ONR-YIP) award (N00014-17-1-2425). The program manager is Brian Bennett. K.A. and V.P.D. acknowledge partial support from the Air Force Office of Scientific Research under award number FA9550-17-1-0348. This material is partially supported by the National Science Foundation under grant no. DMR-1929356. K.A. and M.L. also acknowledge the support from the University La Sapienza for the Visiting Professor Program 2018 (Bando Professori Visitatori 2018) as well as for the Sapienza Research Program 2017 (Progetti di Ateneo 2017). The material preparation was supported by the National Science Foundation under grant no. ECCS-1953803. A.A.M. gratefully acknowledges support from the Ryan Fellowship and the International Institute for Nanotechnology (IIN) at Northwestern University. This work made use of the EPIC, Keck-II, SPID, and Northwestern University Micro/Nano Fabrication Facility (NUFAB) facilities of Northwestern University’s NU ANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720319) at the Materials Research Center; the IIN; the Keck Foundation; and the State of Illinois, through the IIN.
Keywords
- Fabry-Perot cavity
- active tuning
- optical phonons
- phase-change materials
- vdW materials
ASJC Scopus subject areas
- General Materials Science