Title: Casimir Self-assembly as a Tunable Polaritonic Platform
When: Thursday, July 06, (2023), 11:30.
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor).
Speaker: Timur Shegai, Department of Physics, Chalmers University of Technology, 412 96, Göteborg, Sweden.
In this talk, I will summarize our recent experimental attempts to realize strong light-matter interactions using a concept of Casimir self-assembly [1, 2]. The latter opens exciting possibilities for creating planar microcavities with a pronounced Fabry-Pérot resonances in the visible and near-infrared spectral ranges. The effect is made possible through a combination of repulsive electrostatic and attractive Casimir-Lifshitz interactions, giving rise to a stable equilibrium at ~100-200 nm separation distances, where the account of retardation effects is already required (see Figure 1). We use colloidal gold nanoflakes, a few microns across and about 20-30 nm thick to create stable planar microcavities at room temperature and in an aqueous solution. The colloids are electrostatically stabilized by cetrimonium bromide (CTAB), which can be screened by the ionic environment of the solution. I will discuss ways to scale and control Casimir self-assembly through a combination of top-down nanofabrication and colloidal chemistry.
References
- Munkhbat, B. et al. Nature 2021, 597, (7875), 214-219.
- Schmidt, F. et al. Nat. Phys. 2023, 19, (2), 271-278.
