jpphotonJournal of Physics: PhotonicsJPhysPhotonicsJ. Phys. Photonics2515-7647IOP Publishingjpphotonabeb5510.1088/2515-7647/abeb55abeb55JPPHOTON-100321.R1PaperFocus on Phase Change Materials for PhotonicsPCM-net: a refractive index database of chalcogenide phase change materials for tunable nanophotonic device modelling0000-0003-0448-7699KimHyun Jung12 * hyunjung.kim@nasa.govSohnJung-woo3HongNina40000-0002-6432-6515WilliamsCalum5HumphreysWilliam2 National Institute of Aerospace, Hampton, VA 23666, United States of America NASA Langley Research Center, Hampton, VA 23666, United States of America Institute for Life Science Entrepreneurship, Union, NJ 07083, United States of America J.A. Woollam Co., Inc, Lincoln, NE 68508, United States of America Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom

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01420211832021183202132024008271220202912021232021232021© 2021 The Author(s). Published by IOP Publishing Ltd2021 Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Abstract

The growing demand for multifunctional nanophotonic devices has led to the exploration, and utilization, of a plethora of exotic electro-optical materials. Recently, chalcogenide glass based phase change materials (PCMs) have shown utility as a tuning material for a range of nanophotonic devices. Owing to their low loss, ultrafast switching speeds and wide waveband operation, PCMs are integrated in an increasing number of next-generation tunable components, including integrated photonic switches, metasurface optics and tunable spectral filters. Nonetheless, modelling of PCM-based devices is challenging—both in terms of accurate representation of experimentally derived material properties in different phase states, and standardization of results across the research community. Further, as each device requires optimization of specific performance metrics dependent on their respective application, any inaccuracies will lead to erroneous outcomes. In this work, we introduce PCM-net (http://nekocloud.com/pnet/): an online database of the complex refractive indices of a variety of chalcogenide glass PCMs (such as GeSbTe), as an accessible and indexed repository for data sharing across the PCM community. Refractive indices (n) and extinction coefficients (k) between amorphous and crystalline states are directly extracted from experimentally derived data in numerous academic research articles, and collated into the material resource database. Due to the inaccuracies associated with our data collection methods, this data is supplemented with additional computationally generated data, obtained through WVASE® —a commercial ellipsometry analysis software package. To demonstrate the utility of PCM-net, we provide a NASA application-driven device optimization example using the optical properties of PCMs collected with our database. We anticipate the database providing great use to the PCM community and coordinated research efforts enabled by PCM-net will promote the shared repository for the selection of appropriate PCMs for tunable nanophotonic device design for a range of applications.

online databaserefractive indexphase change materialnanophotonicsoptical metasurfacePCM-netdevice modellingccc2515-7647/21/024008+15$33.00printedPrinted in the UKcrossmarkyes