Phase change material programmable visible photonics*

Chalcogenide phase change materials can exist in multiple structural states at room temperature. There is a large difference in the electrical and optical properties between the structural states of these materials. Importantly the phase transition time can be just picoseconds [1], and this makes these materials ideal for both optical and electrical data storage[2]. Indeed, they have recently been commercialised in Intel’s Optane memory[3].

The most common data storage materials exist along a pseudo-binary compositional line between Sb₂Te₃ and GeTe. These materials tend to have a small electronic band gap and consequently strongly absorb visible light. This means that it is challenging to use these common PCMs for many visible photonics applications.

We will discuss how phase change materials can be used in visible photonics. We will discuss the plasmonic property of the common phase change materials and also introduce a new phase change material with an electronic band gap of 2 eV[4]. We will discuss the prospect of using electrical fields to control phase changes in these materials. We believe these results will open new opportunities to design programmable photonics devices that operate at visible wavelengths.
[1] L. Waldecker et al., Nat. Mater., 14(10):991–995, 07 2015.
[2] M. Wuttig and N. Yamada. Nature Mater., 6(11):824–832, 2007.
[3] L. Hoddeson and P. Garrett. Physics Today, 71(6):44–51, 2018.
[4] W. Dong et al, Advanced Functional Materials, 6:1806181, 2019.