Abstract
Control over the interactions between light and matter underlies many classical and quantum applications. In recent years, 2D layered semiconductors have gained prominence for optoelectronics because of their strong excitonic effects and capacity for van der Waals assembly. One of the unique features of these monolayer materials, the valley pseudospin, can be manipulated by controlling the local properties of optical fields. Here, we discuss two manifestations of this optical control across different regimes of coupling. In a strongly coupled regime, we discuss the dynamics of valley-polarized hybrid light-matter states, or exciton-polaritons, in a monolayer MoS2 embedded in a microcavity. Different dynamics of valley-polarized exciton-polaritons can be accessed with microcavity engineering by tuning system parameters such as cavity decay rate and exciton-photon coupling strength. Comparison of predictions and measurements demonstrate the ability to intentionally modify exciton-polariton valley characteristics, illustrating the microcavity as a tool for manipulating and engineering valley dynamics in 2D materials. In the weak coupling regime optical selection rules give rise to the valley-selective optical Stark shift. We discuss recent advances in probing this effect with improved sensitivity. Both of these complementary approaches show how the valley structure of monolayer materials yield interesting light-matter phenomena that allow tuning of optical properties.
| Original language | English (US) |
|---|---|
| Title of host publication | 2D Photonic Materials and Devices II |
| Editors | Hui Deng, Carlos M. Torres, Arka Majumdar |
| Publisher | SPIE |
| ISBN (Electronic) | 9781510624825 |
| DOIs | |
| State | Published - 2019 |
| Event | 2D Photonic Materials and Devices II 2019 - San Francisco, United States Duration: Feb 6 2019 → Feb 7 2019 |
Publication series
| Name | Proceedings of SPIE - The International Society for Optical Engineering |
|---|---|
| Volume | 10920 |
| ISSN (Print) | 0277-786X |
| ISSN (Electronic) | 1996-756X |
Conference
| Conference | 2D Photonic Materials and Devices II 2019 |
|---|---|
| Country/Territory | United States |
| City | San Francisco |
| Period | 2/6/19 → 2/7/19 |
Funding
The research described here has been supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. DE-SC0012130 (cavity exciton-polaritons) and the Office of Naval Research under grant number N00014-16-1-3055 (ultrafast valley manipulation). Sample preparation and characterization were partially supported by the National Science Foundations MRSEC program (DMR-1720139) at the Materials Research Center of Northwestern University. This work made use of the EPIC and KECK-II facilities of the NUANCE Center at Northwestern University and the Northwestern University Micro/Nano Fabrication Facility (NUFAB), which have received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the Materials Research Science and Engineering Center (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. The authors thank H. Bergeron, I. Balla, J. D. Cain, M. C. Hersam, and V. P. Dravid for preparation of CVD-grown materials used in several of the experiments outlined here.
Keywords
- 2D materials
- Exciton-polaritons
- Kerr rotation
- Stark effect
- Valley pseudospin
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering